I've never been in a shop that wouldn't take a £50, I've never seen a cashier '**** themselves' at the sight of one, and I certainly don't '**** myself' at the sight of one, or a wad of them.
It's money. Scribble it with the magic pen and put it in the till. Drama!
why do shops scribble a uv pen on notes anyway? They all must be covered in squiggles by now.