Ahh crap, now I find out. I donated £5 to a "cause" a few months ago, it was a "Charity fighting knife crime", I told them I didn't have any cash and they pulled out a card reader connected to an iPhone and they insisted on a "tenner" stating that someone had given them £50 quid this very same day. It was near to Old Street Station.
You still living in Streatham? Or Streatham Hill rather, it more posh!
A charity fighting knife crime? Sure that is a job for the police