After about 5 trips to each place I finally completed all I aimed to harvest on Friday. I got 5 sets, 3 of which are for customers, so there are two spare sets available.
The photo at the bottom shows the whole lot, sorry it is not great, I couldnt find spare flashgun batteries and did not want to move them all to a better location.

The London Empire (Casino at Leicester Square) has 12 low limit (relatively ) tables in play. I have no clue why they chose the numbers they did (the actual signs on the tables run 1 straight thru 12) but they did
The tables are in banks of 4 - £1 minimum tables 1, 2, 3 & 17 - 9, 10, 11 & 12. £2 tables 5, 7, 8, 18.
Some tables have one or more colors designated for higher buy-in only, presumably more secure for them if a player wants to switch without moving tables. There are 8 colors in use on each table. Orange, Yellow, Blue, Green, Lilac, Beige, Grey & Brown.
I got all 8 colors from the 8 £1 tables. I got 2 different colors from each of the £2 tables to make a further matching set of 8. 72 different chips total. The actual buy-in for one of each was £80 ($163). It cost me 10% over approx to get them. If I add a bit for gas/parking for the few trips I made specifically to get these chips and nothing else, plus shipping from here and a bit for paypal, I need $225 for the set of 72.

The Isle at Coventry also has 8 of their 10 in play tables in banks of 4 but table minimums are mixed up, and also different colors are fixed at different minimums on most tables. Coventry is 'out in the country' so it attracts any clientele it can get from a fair radius as there are no other decent size casinos nearby. Therefore its like a zoo most of the time I talked to a few dealers and pit bosses on Friday and they say its a nightmare with all the mixed minimums and different limit tables. Each table has 7 colors in play, being the same as the London Empire but with no yellow. The yellow "Phuket" chip in the scan is explained below. Each table has the name of an Island - Ibiza, Mauritius, Phuket, Bermuda, Zanzibar, Seychelles, Tahiti, Hawaii, Jamaica & Bali. I got all 7 colors from the first 7 listed (which are a mix of 50p/£1/£2 minimum). The last 3 were a mix of £1/£2 & £5. I declined the £5 colors, leaving a total of 14 different out of the 21 at £1/£2 which I got. With the yellow Phuket there are therefore 64 different chips. The buy-in for one of each came to £78 ($159) so I need $220 shipped for the set of 64.

Now onto that yellow chip I reported here after I had been to the opening, and that they had teething problems etc. so there wasnt much play (and I was primarily there for cash chips anyway). As I got there before it got busy I played a couple spins on one table just to get a color to show to people at the convention. By chance I got yellow. I did notice when I looked around that all the other tables only had 7 colors so I cheked to make sure they all had the same 7. When I went back to the Phuket table to see if maybe they only had 7 including the yellow, I saw they had taken the yellow out of play but still had the same 7 colors as the other tables. I asked the pit boss why. He explained that as it was almost identical to the £1 cash chip, security had trouble identifying them on camera so they were trying them on one table only while Gaming were there for the first hour or two of opening. With the mix of tables and minimums they considered it totally unplayable so that single yellow chip was only actually in play for half an hour. Pure luck that was the color the dealer gave me first up and that I had pocketed 5 of them.