In reply to ddu32: I love Wyndcliff Quarry, it has some great routes, but given your potential starting grade I think you might struggle to find something you were happy on there.
I've only been to Tirpentwys once - at the time I'd done quite a bit of stuff outside and had lead several f6b routes - I struggled to get up a 5 there, something about the angular sandstone made it seem very hard to climb. Probably just because all my leading had been on limestone up to then, but I know I can away disheartened.
Ban y Gor I struggle with the layout. Cos of the location there aren't any photo-topos as such and actually finding the route you want to climb can be a right pain.
So I hate to say it, but my money would probably be on the 30' wall at Tintern. Yes the place is a great ugly hole in the ground, yes there is a lot of choss about (but the 30' wall is totally sound), but really I reckon this is one of the best places around to just get on lots of lower grade routes without faffing about.
Wear a helmet though!!