Unfortunately that's not even a surprise. I've stopped having a £10 note in my hand when stood at the bar in London wanting two drinks. Which to the annoyance of my wallet is about twice a week at the moment.
I paid £11.70 for a doule gin/tonc (Islington area, beer garden type pub). And then I kept doing again and again.
I once paid over £15 for a pint and a glass of white wine for the missuss. That was at a hotel in Ascot AND it was over ten years ago. To say I was shocked was an understatement, I even asked her to give me my change, she said she had. As we were on a Xmas do surrounded by the wife's colleagues I didn't make a fuss. BUT if we'd have been on our own .....