Ditto, over here you're allowed VFR on top as a basic PPL right, with limitations on ascertaining positive position fixes at intervals of not less than (I don't remember!). however the book actually suggests that visual position fixing above >4/8ths is not 'feasible'. If you're signed off on VOR/NDB you can fly over 8/8ths, but you'd better hope for a hole to come down through!
All of which is utterly irrelevant if you hold a JAA UK PPL. Sorry!