Originally Posted by
ajGoes
You can't exchange twenties for hundred-pound notes ... because the largest banknote is £50.
You should be able to get some at a bank. You can exchange your old, round one-pound coins for new dodecagonal ones at the same bank.
Ah, thanks; I could've sworn I've had a 100-pound note in my possession at one point in my life, but that would be impossible according to Wikipedia.
Thank you for your response, it was very helpful.