Closest Limestone bouldering to Newcastle:
The Cove, a genuinely good quality venue, although you have to resort to eliminates if you want anything too hard.
Houghton graveyard: where every visitor gets a first ascent as the holds are never the same twice. gr and myself bolted some of the lines there and kept drilling through into holes inside the surface, which we tried to fill with glue. Alot of glue. Steve Crowe cunningly reduced the frequency of this happening by placing half the number of bolts in the routes he did.