Oxfam Sunday - Wombats and Dodgy £20's

I went up onto the top deck today to take over from Lautaro (it's a Spanish name, but he's a Scotsman), and he'd left on the CD player a reasonably decent compilation, in which was this catchy number from those lovable scousers, The Wombats:

It was a fairly uneventful shift: people seem to be concentrating on getting presents for Christmas and leaving us except for cards and wrapping paper.
I'd run out of £10's at one point and asked Mark to bring any up. He examined one of the £20's in the till and started holding it up to the light. He explained that he had a conversation with one of the tellers at the bank and he got a few tips on how to spot a fake. I compared the one he was looking at with another and they were almost identical, but there is a watermarked £20 which was slightly off in the "fake" note:

If it is a fake, it's a good one! It passed the marking test with our security pen.

I also got a Penguin Special from John, The Hidden Persuaders by Vance Packard:

It's about advertising, S185, published in 1960.