£5 note - big and white

In the 50s, a £5 note was large (maybe 7" X 5" - but please comment if you think that is wrong) and printed black on white one side only. £5 was a lot of money back then - you would probably need over £100 today to buy what it could then. They were not very common and, if one paid with one, it was normal to be asked to sign the back and add contact details.