I have flown GA aircraft in the UK, USA, Spain and South Africa. In the UK getting anything other than FIS is almost impossible. In the US I have never had a request for "Radar Following" tunred down. This is despite flying in busy airspace around LAX, SFO, MCO and PHX. As more GA and ultimately CPL/ATPL pilots, do the vast majority of their training in the US the expectation of radar services and confusion over their UK equivalents will increase. The CAA should insist on mandatory training in the UK for all those CAA PPL's issued in the US. I can speak from experience as I did my license over their and when I returned to the UK I was less than fully aware of the difference in services.