I find that improbable (but possible as anything is when we know so little) for the reason I state below.
AR tables usually have 7 different colour chips with possibly another colour or 2 as extras just in case there are problems with similar/clashing colours (but not something that happened often). Obviously if lots of the same colour went missing then it was also an option for security reasons (again, I never saw it but it's possible). When I started, colour blindness was something that was checked and tested but in the earlier days, people just blagged it. I knew at least 3 people who worked in London who were very "old school" amd just got away with it for 30 years.
Maybe there were more than 1 table (or a double as mentioned before) with the red on one and the black on the other (as they could have had different minimums).
Maybe somebody messed up the re-order or the process had changed when the others were made.
The smaller ones could have been for a certain punter and even though it was just a provincial club so it is doubtful, maybe junkets (which did happen even after the gaming act especially at the high end clubs in London) were given free chips. Improbable but still a possibility as nothing can be ruled out at this moment in time.
Maybe the lunette ones were thought of (and marked up) as cash or even higher values, we just don't know for sure. As I've said, when you buy in at a 25p minium table for instance, that is the value of the chipsyou are given unless the punter specifies they want them at a higher value.
They could even have been used for other things (free dinks or meal) although paper tickets would have been more practical I suppose.
There are other possibilities I expect but it gives an idea that many things are "possible" and can't be discounted unless we find out for sure.
It would be great to find actual cash jetons but at the moment I am leaning towards normal table chips being used for larger payouts or when they cashed in until we find some of those.
Just my opinion as somebody that worked in UK casinos and know a few things about how they worked but feel free to take with a pinch of salt.