As I have stated many times, even going so far as to ask an old Playboy employee (or 3) about them and supplying a French roulette table photo along with other stuff to confirm, I always thought that they were French roulette JETONS but thanks for the extra information.
According to somebody who worked at the CHC in the mid 60s, they also used jetons on BJ too but I expect that it didn't last long due to them probably being awkward to work with and slowed the game down (possibly).
Le Cercle's £1 jeton was probably used as a session payment as when it opened it only had 3 Baccarat/chemin de Fer tables. They were probably used on the French roulette tables too when they were brought in.
Look after yourself.