In the US there is no type rating for airplanes less than 12,500 lb max certified TOGW, except for turbojet powered airplanes. Endorsements are required for tailwheel and complex airplanes, but they are general endorsements that cover all airplanes of that description. I don't know what the UK or JAA limit is.
So, a PPL holder with a complex airplane endorsement could theoretically fly any single-engine piston or turboprop airplane with tricycle gear with max TOGW of less than 12,500 lb.
Still, insurance requirements and common sense would restrict a pilot with only C172 experience to a MUCH smaller subset...