Despite the UK supposedly switching to the metric system decades ago, there's still a way to go to finish the job. I'm sure things would speed up if shops were legally obliged to accept the advertised price
[Burger shop]
Me: a quarter pounder please
Them: here you go
Me: thank you. Here's 25 pence
[TV shop]
Me: I would like an HDTV please
Them: this one is 1080p
Me: great, here's eleven quid. Keep the change