The Grosvenor Casino is actually a group of at least four casinos in the London
area that actually have different names but many use the same chips. The main
one is the Victoria Casino just North of Hyde Park. The set you may be referring to are 20 pence, 25 pence and 50 pence chips that all depict different
gambling themes. They are very colorful chipcos and were issued about three
years ago. i was in London in December of 1997 and they were issued within
amonth or two of my visit according to casino personel. I visited 9 different
casino while I was there and 5 of the 9 had differnt chips except for the
Grovenor Group. I had to become a member of each one. You have to sign up
24 hours in advance of going in. Some even want you to pay a membership fee.
I hope this info is of interest to you.