In reply to Slackboot:
Regarding forged notes, I sold a washing machine a few months ago and the guy that came to collect tried to pay me in what I'm sure were fake £20 notes.
They were Northern Irish Danske Bank issued - long story, but I had the chance to measure them and they seemed to be the wrong size and didn't feel quite right.
In the end, I insisted on being paid in Sterling notes and he changed them. Still not sure if he was actually trying to scam me or he'd accepted them in payment from someone else and honestly didn't know - he seemed a decent enough chap.