Your question is not that daft, not to me at least. For as far as I understand, it does not matter in this respect whether one flies on a PPL or an ATPL or an NPPL(S)* or whatever - what matters is whether one is allowed to fly the rules for the given area. VFR is the basic, allowed everywhere to all pilots, I believe. The trouble comes when wanting to fly in airspace only allowing IFR and not having the appropriate rating.
Another difficulty could be the airspace being only open to aircraft carrying certain equipment - a transponder is the obvious example - but that's about the craft, not about the pilot.
*NPPL submarine - surely the UK must have such a thing defined among its bewildering variety of licenses