Silverlocks

Note that quite a few ISA products (Vanguard, for example) have an online facility that let you put money in and trade via their web interface.  However, they only offer purchases of funds available through their app.  I'm not sure how (or even if) you can use this type of ISA product to buy shares from outside their ecosystem, so I'd talk to the vendor and find out what is and isn't possible.

A little glossary here:
ISA = Individual savings account.  Lets you invest £20,000 pa in eligible funds and other instruments that qualify and shield the investment income from capital gains tax.  You still have to pay income tax on the money you invest.  'Stocks & Shares' ISAs allow you to purchase shares or qualifying funds.  Not all funds are eligible to be traded through an ISA, although I'm not sure what the criteria that qualify or disqualify a fund from this are.  You may need to engage a stockbroker in order to buy the shares, but I would see a financial adviser to see how to set this up.
SIPP = Self Invested Pension Plan.  This lets you invest up to £40,000pa into pretty much anything including vaulted PMs (take a look at Sharps Pixley for an example of such a service) - and (importantly) wheel and deal in the investments if you so desire.  However, it's a bit more restrictive about getting the money out as it's a pension.  You can claim investments into a SIPP against income tax but I think you have to pay tax on money withdrawn.  They are designed (as the name suggests) for pensions.
ETF = Exchange traded funds.  These are funds - mutual and index funds typically - that can be traded through investment vehicles such as an ISA.  'Exchange Traded' means that ordinary plebs like you and me can buy or sell a share in the funds and (most importantly) can flog the funds at pretty much any time.  
 
 

Might be worth seeing if you can do it through an ISA or SIPP to shield you from capital gains tax and/or income tax.  See a financial advisor on how to set that sort of thing up.  You can also do vaulted PMs through a SIPP, which is more restrictive than an ISA but allows you to claim it off against your income tax or self-assessment tax.
I am not a financial advisor, nor do I play one on TV.  You will probably need to see someone about setting these up.

I think the good and bad thing with sovereigns is they're boring.  With silver you can buy 10 coins or a tube or a bar for a sum of money accessible to most people and feel you've achieved something.  Getting enough gold together to make it look like you're doing something concrete is a much bigger hurdle.  My entire silver stack wouldn't buy even half a tube of sovs.  Not so much dopamine reward.
Nonetheless, I'm pivoting away from silver to a mix of sovs, occasional 1oz bullion and maybe other stuff if it comes up at the right price, plus a small sideline in collectibles.
 

If my coins have been stored in my bowel, do I still get 1% above spot?

Sure, and thanks for posting those definitions, of which I was fully aware. It's just that there are other meaning of the word, including:
"The bowel. The bowel is part of the digestive system. It is made up of the small bowel (small intestine) and the large bowel (colon and rectum). The small bowel is longer than the large bowel but it gets its name from the fact it is much narrower than the large bowel."
To avoid ambiguity about where our stock is stored, I would normally chose to use a different word.
😎

So, most of my Q3 stuff is in - astute observers will notice that there's a missing pile of Krugerrands, and there's also a bit of numismatic stuff still en route.  Perhaps I will take another photo once all the Q3 stuff is in.  It's starting to look like a stack now, though, so -

Q4's plan is a bit more prosaic and longer on gold - a few sovs, a 1/4 oz Tudor lion and maybe a 1oz brit.  Possibly some other bits and bobs of silver in the numismatic space.

And the last of the Q3 silver has arrived.  I also got a 1kg copper bar for ***** and giggles.  According to the vendor it's .99999 fine; not sure whether to take that with a grain of salt. Now, the emphasis in silver is off straight bullion and onto collectibles and semi-collectibles such as the dollaridoos.  I may pick up the odd tube of Brits if it happens along at the confluence of price and available cash.
It's starting to look like a stack now.  Q4 is mostly gold, as is 2023

I think the good and bad thing with sovereigns is they're boring.  With silver you can buy 10 coins or a tube or a bar for a sum of money accessible to most people and feel you've achieved something.  Getting enough gold together to make it look like you're doing something concrete is a much bigger hurdle.  My entire silver stack wouldn't buy even half a tube of sovs.  Not so much dopamine reward.
Nonetheless, I'm pivoting away from silver to a mix of sovs, occasional 1oz bullion and maybe other stuff if it comes up at the right price, plus a small sideline in collectibles.
 

I think the good and bad thing with sovereigns is they're boring.  With silver you can buy 10 coins or a tube or a bar for a sum of money accessible to most people and feel you've achieved something.  Getting enough gold together to make it look like you're doing something concrete is a much bigger hurdle.  My entire silver stack wouldn't buy even half a tube of sovs.  Not so much dopamine reward.
Nonetheless, I'm pivoting away from silver to a mix of sovs, occasional 1oz bullion and maybe other stuff if it comes up at the right price, plus a small sideline in collectibles.
 

Sovereigns always seem like the sensible option, but then you're browsing and that cool bar gets shared

And the last of the Q3 silver has arrived.  I also got a 1kg copper bar for ***** and giggles.  According to the vendor it's .99999 fine; not sure whether to take that with a grain of salt. Now, the emphasis in silver is off straight bullion and onto collectibles and semi-collectibles such as the dollaridoos.  I may pick up the odd tube of Brits if it happens along at the confluence of price and available cash.
It's starting to look like a stack now.  Q4 is mostly gold, as is 2023

One interesting thing about information...
Seek and ye shall find!
As for the invitation, I would prefer to decline, thanks.
Nothing personal you understand!
😎

Or...

RM don't even make the gold planchets anymore, I believe they buy them off of the Perth Mint.
They always go on about the Labour government of the 2000's and the war in Iraq but Gordon Brown selling off the nations gold is hardly ever mentioned, that was a travesty.
Great lets hold a load of different currencies all inflating away to zero at differing rates instead of gold, future generations will really thank you for doing that!
 

Best advice I've seen is to avoid proof coins until you know what you're doing.  You can make a lot on them as collectibles but it's also possible to lose a lot.  I'm just in startup mode and I've got no short-term plans to buy any proof coins, especially high-end gold ones.  My Brilliant Uncirculated 2p worth - stick to sovs and maybe 1oz bullion until you've got reason to believe you know why something else is a good investment.
That's not to say that collectibles aren't worth investing in, but you're rather jumping in the deep end with that one.

Sovs are a little counter-intuitive but it took me less than a month of hanging about TSF to figure that out.  They've got much lower spreads than other 1/4oz gold and if you trade them here, the going rate is about spot+£10-15, buy or sell.  Given their liquidity here (and presumably on the secondary market in general), sovs are pretty much a no-brainer.

Best advice I've seen is to avoid proof coins until you know what you're doing.  You can make a lot on them as collectibles but it's also possible to lose a lot.  I'm just in startup mode and I've got no short-term plans to buy any proof coins, especially high-end gold ones.  My Brilliant Uncirculated 2p worth - stick to sovs and maybe 1oz bullion until you've got reason to believe you know why something else is a good investment.
That's not to say that collectibles aren't worth investing in, but you're rather jumping in the deep end with that one.

Sovs are a little counter-intuitive but it took me less than a month of hanging about TSF to figure that out.  They've got much lower spreads than other 1/4oz gold and if you trade them here, the going rate is about spot+£10-15, buy or sell.  Given their liquidity here (and presumably on the secondary market in general), sovs are pretty much a no-brainer.

Sovs are a little counter-intuitive but it took me less than a month of hanging about TSF to figure that out.  They've got much lower spreads than other 1/4oz gold and if you trade them here, the going rate is about spot+£10-15, buy or sell.  Given their liquidity here (and presumably on the secondary market in general), sovs are pretty much a no-brainer.

Best advice I've seen is to avoid proof coins until you know what you're doing.  You can make a lot on them as collectibles but it's also possible to lose a lot.  I'm just in startup mode and I've got no short-term plans to buy any proof coins, especially high-end gold ones.  My Brilliant Uncirculated 2p worth - stick to sovs and maybe 1oz bullion until you've got reason to believe you know why something else is a good investment.
That's not to say that collectibles aren't worth investing in, but you're rather jumping in the deep end with that one.

Underrated advice 👏 

The spread on sovs tends to be rather smaller than other 1/4oz coins - maybe 5-7% from a dealer or less if you buy lots.  However, if you get them here the spread is pretty much nonexistent.  Unless they are a key date they tend to go for about spot + £10-20 here and they're very liquid.  Just in the last few weeks I've seen folks rock up with as many as 50 or 100 sovs and flog them all within a few days.
I started down the silver route, but I'm dialling silver back to the odd collectibles that might appreciate in value.  I'm not sure if I'll be buying much if any bullion silver in the future, although I might get the odd tube of Brits or some such if they come up at right confluence of price and spare cash.  I do think I might collect a bit of stuff for the birth dates of the spawn, but this will be a bit of a sideline.
My basic stacking approach is to get at least one sovereign per month, plus whatever is going at the right price - maybe some 1oz or other coins, again if available at the right price. I've got in mind a figure of 100g/year or thereabouts, and I expect sovs will be doing the heavy lifting.  I think the way to do it here is to buy the odd cheeky sov or two if some come up for sale, and get stuff from dealers at the end of the month or quarter if you've not blown it on shiny stuff here.
On the Indonesian side, P.T. Antam bars are pretty much where it's at, so we will be accumulating some gold there as well.  However, this gets you rogered for 11% VAT there (although this may change) so it's not such good value.

And the last of the Q3 silver has arrived.  I also got a 1kg copper bar for ***** and giggles.  According to the vendor it's .99999 fine; not sure whether to take that with a grain of salt. Now, the emphasis in silver is off straight bullion and onto collectibles and semi-collectibles such as the dollaridoos.  I may pick up the odd tube of Brits if it happens along at the confluence of price and available cash.
It's starting to look like a stack now.  Q4 is mostly gold, as is 2023

This is what I'm currently using, same idea as the sovs. Purchased on here and think they have to be imported from America. 
https://www.thesilverforum.com/topic/67533-air-tite-tube-h32-1oz-gold-britannia’sqb-etc/