Lots of good advice but one thing that hasn’t been mentioned is the differences in airways, which took me by surprise when I made the opposite move from the UK to Canada many years ago.
Unlike North America where you can fly along low-level airways in VMC without talking to anyone, in the UK all airways are Class A and VFR flights are not allowed.
This is a very good guide to UK procedures:
https://www.bfgc.co.uk/VFR_Guide.pdf
PS As Genghis mentioned, flying in the UK is expensive. From a North American viewpoint, it is shockingly expensive!
