In reply to ConstaBern:
The only place I know of that's bolted in Cornwall ( to a degree) are the quarrys on Bodmin Moor. These are a bit of a mission from where you're going. And the routes are those which really don't have a sniff of natural pro on them, which could also be interpreted as a hold! ie the routes are hard. Without looking at the guide book, the easiest route is probably (Cornish) 6b!
However, that said, if you were more local I'd suggest they were well wory a visit give the quality of the granite in the area.