> The problem was that £50 notes were most likely forged, I thinkThat was what we were told back when I worked in a small shop in a theme park in the late 90s. That combined with the fact that because we rarely saw them people tended to be worse at picking out fakes than they were with smaller denomination notes.
We were to ask people to go to the cash office at the front of the site to have large notes swapped for smaller currency, £10 and lower. The reason we gave the customer (which as you mention had the benefit of also being true, even though I was very much given the impression it wasn't management's primary concern) was that it would take all the change from out tills. We would accept £20s, though the sign up front suggested they be changed first too.
> solution surely isn’t to get rid of the notes as that just shifts the forgery to the next note down
The recognisability helps with lower denomination notes though. And taking a forged £50 is more of a hit than taking a forged £10 amongst others.
> Surely instead the solution would be higher valued notes being created.
The solution we are heading towards, more rapidly now due to C19's effects, is cashless. I still have a few coins in my running pouch in case I need to use a non-free public convenience and a few of notes in my wallet just in case the cards fail, but I don't think I've actually used cash at all in the last 12 months and that may remain the case once This is all over (there is a local corner shop that won't take contactless or other card payments for less than £10 - I simply don't go to that shop any more as that is inconvenient for me for single small items so I do without for now or walk further, and for needs >£10 I'll walk further to a larger store with more options anyway).