I agree training in a controlled environment is a good thing, but in respect of taking 10 hours of extra dual flying after an intensive course in the US, I think it depends where in the US you went and where in the UK you're flying. I trained in busy California airspace with really hostile weather. Came back to the UK and went flying up in Scotland, and it was far less demanding - weather happened to be fine for weeks, the mountains half the height, virtually no other traffic anywhere, and ATC far more relaxed. And, at least when the weather is bad, I'm familiar with it, unlike all the desert and tropical stuff going on in foreign parts.