In reply to alexrp: Baggy is probably the best bet for accessible (in both senses of the word?) culm, though I've not been there personally so can't tell you more.
What's culm? A weird slatey feeling type of metamorphosed sandstone / shale. I believe. Weid stuff, but makes some very impressive slabby crags.
Maybe the Dewerstone for granite.
It's not my neck of the woods, so use the crags database on here.