David, you should forgive me if the foregoing makes no sense, since apparently our community psychics have decreed that English is not my first tongue. (Incidentally English is a dialect, not in fact a language.)
It's all very simple. CAP393 (link is a few posts above) shows you the rules of the air in the UK. Since you're interested in VFR flying, then rules 24 though 27 inclusive are the only rules you need concern yourself with. The _privileges_ are found in Schedule 8 of the ANO. _Visual Flight Rules_ in section V of section 2 of the aforementioned CAP. The VFRs apply to all civilian aircraft in the UK. Whatever _privileges_ you are granted by an FAA PPL must not be exercised if they are not permitted by rules 24 through 27 inclusive.
[Free translation to Gaelic and Finnish available upon request.]