In reply to yoshi.h:
Godrevy is excellent wave washed slate, but suffers from the beach crag problem of changing sand/pebble levels that mean climbs change grade or appear/disappear occasionally when there is a big storm.
Helman Tor is worth a visit, but my favorite when I visited Cornwall last year was Trewortha Tor:
Trewortha Tor#overview
A 15 minute walk in and no proper topo guidebook, but i found some fascinating problems of every style, on mostly solid granite.
Love it there and sure you will have a good time.