@Petra Sure!
1) First of all, the dates 1916 (London mint - no mint mark) and 1911-C are quite scarce, so when you see them come up you should be wary and examine if they are fake. Of course it could be a batch of hoarded sovereigns which are genuine, although there is a very low possibility of that happening.
2) You can notice that some of them have a date of 1919 with no mint mark, therefore London mint. That can't be correct, since London sovereigns weren't minted that year.
3) On some of the coins there seems to be an "B.B.P." instead of "B.P.".
4) Details on the coins. Some examples are:
a) 1st photo, 1st row, 1st coin from the left: The sword and leg of St. George lack detail and seems to be "integrated" into the body of the horse. There should have been clear lines and details on both the aforementioned parts.
b) 1st photo, 2nd row, 2nd coin from the right: Details are all wrong, although I would say that the leg and hair streamer of St. George seem to stand out.
c) 1st photo, 2nd row, 3rd coin from the right: Details are absent and also the date "1916" looks like it was vertically "squeezed".
d) 1st photo, 3rd row, 3rd coin from the right: Again the details are all wrong, of which the belly of St. George and also the details on the dragon stand out. Plus, under the dragon there is a "canyon", which shouldn't be there.
These are some of the many wrong things that I can tell you on the spot. Using a photo of an original sovereign will help you greatly in comparing and identifying the wrong thing you see.
Cheers!