dicker

Sadly, my thoughts too.
edit: but a reputable coin dealer wouldn't have done that, or indeed ever needed to. that's the work of a pawnshop/cash for gold outfit, i'd wager.
Sorry OP, we're not attacking you.

I wouldn't bank on it. As previously said, many dealers have been fooled by this coin, I have seen more than a few obvious fakes in auctions over the years and you'd be surprised by which auction houses as well😮
Allowing for the fact that photos rarely tell the full tale and these are good but not top notch, I would guess this coin is fake but one of the pretty good ones with none of the obvious faults often seen. There seem to be several "poor" details that appear to be too indistinct to be genuine.
If it were me I would get it graded as soon as. The money will not be wasted; it is a decent grade and having it in a holder will increase it's value substantially. If it turns out to be fake, well at least you'll know☹️
 

With counterfeit certificate as well.  
 
Vile. 

With counterfeit certificate as well.  
 
Vile. 

Thanks for sharing will save that to have a proper read

Todays Binlord is either being fraudulent or is just clueless.
- Half Sov advertised as a Sov
- Invalid year and mint combination for a Half Sov
- Listed in category “Penny”
- Described as “one of the finest Victorian Shield sovereigns we have seen. Proof like with mirrored fields and basically as it was the day it was struck - stunning example”
What an utter Binlord.
I have emailed him and told him what’s wrong with his listing.  I don’t often get a reply…..but will post here if I do!
https://www.ebay.co.uk/itm/304753409960?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=BwJB_geRSgC&sssrc=2349624&ssuid=bYgKomkjQOW&var=&widget_ver=artemis&media=COPY
 
 

I had a chance of a 1887 double that looked too good to be true. Reading Mr Chards piece on the subject changed my mind ( Thank You ), a lucky break. 

My favourites are hazelnut.  

I don't think it's a proof coin.
I don't think those 3 marks are edge knocks - they are too specific for that.
I agree with the other posters who say that this particular coin is often faked.
So if it was my own coin - I would be seriously considering if I wanted to keep it.  If I didn't want to keep it then I would probably look to sell it as an ungraded coin, but I appreciate that any potential buyer would need convincing as to its genuineness - so that might take you down the graded route.
Unless it had particular sentimental or personal value to me, the filing marks and other imperfections would detract from my enjoyment of the coin.
Personally I would sell it and reinvest the proceeds into other gold coins, even another quintuple from a reputable source if you wanted a coin of that size.  But I'd probably put it into bullion sovereigns, doubles, or 1 oz coins.  
I own five quintuple sovereigns and I love the size and heft of them.
 
Good luck with your decisions.

It’s a good auction with zero buyers fees which is very attractive.  
Frequently coins up for auction that are of interest to me and the customer service is great.  Particularly on the phone!

In my humble opinion that's likely had a file (well, three) across it, possibly it's been to three separate pawn shops, the second and third of which thought the previous mark/marks were suss? Edge knocks happen, but for a trio to appear in the same area up against the idea of non-experts testing for a fake gold coin...? 
It's unfortunate whatever the truth, that said if it's real it's still a nice looking coin🌞
 

The last photo shows off its lovely "proof like" appearance

Now, that looks like real Quality Street!
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Jeweller's file more like!
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With a fork?

It would help people to help you if you name the supplying dealer, and also the "central London dealer", otherwise we are all playing unnecessary guessing games.
You might also be shocked at the number of dealers with "very good reputations", who make mistakes and / or sell fakes with little care for accuracy or their reputation.
For example:
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If they are file marks then I think it would get a "details" grade if it went in for grading - but then you would know for certain whether it is genuine.

Was exactly my thoughts, looks like 3 x file marks.
 

The dealer I originally bought it from has a very good reputation. Sadly retired now.  Good honest and fair priced coin and stamp shops are starting to become a rarity nowadays as more retired due to ill health or age. I use to have the best. Would sell me coins at spot price, sometimes even under.

The dealer may well have noticed edge knocks, but sometimes drawing attention to such things can needlessly antagonise a potential seller.
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There is another possibility with respect to the edge knocks…
Some unscrupulous people fill areas of coins.  In the US it’s called “Coin Doctoring” and covers everything from chemically treating coins, through to disguising marks with dental wax and other fillers.  Often these de-grade over time and the owner only realised years later (or after a coin has been graded)
It could be the case that your coin had been interfered with and the treatment it had received has dissolved or fallen away over time…
https://coinweek.com/opinion/commentary/the-specter-of-coin-doctoring-and-the-survival-of-great-coins-2/

It would partly depend who the "central London dealer" was.
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Assuming you paid substantially less, even in it's current condition ( if geniune,and i mean geniune sovereign rather than geniune gold ) then use it as a trade up coin? Unless its your birth year..in which case, congratulations on both the coin and your incoming Guinness world record 😉 

Believe both @LawrenceChard @dicker are referring to it being a genuine sovereign, rather than questionable gold content. 

There is another possibility with respect to the edge knocks…
Some unscrupulous people fill areas of coins.  In the US it’s called “Coin Doctoring” and covers everything from chemically treating coins, through to disguising marks with dental wax and other fillers.  Often these de-grade over time and the owner only realised years later (or after a coin has been graded)
It could be the case that your coin had been interfered with and the treatment it had received has dissolved or fallen away over time…
https://coinweek.com/opinion/commentary/the-specter-of-coin-doctoring-and-the-survival-of-great-coins-2/

Your first concern should be whether it is genuine, as @dicker mentioned in passing.
It is London Mint, not Sydney, and if you are not sure whether it is proof, then it will not be.
This is probably the most faked of all UK coins, followed closely by the 1887 double sovereign.
There are many obvious fakes, and also some difficult ones made in the 1970s, probably in Beirut.
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