Anyone sitting on paper UK currency might want to get rid of them prior to September 30, it appears. The paper notes become worthless on that date, in favor of the recently released polymer bills.
https://www.bloomberg.com/news/articles/2022-06-22/uk-gives-100-days-to-spend-last-14-5-billion-of-paper-banknotes#xj4y7vzkg
I suspect more than a few of us may be sitting on UK paper currency.
Kevin Slater