Spent most of my first few years climbing on a bridge under the A1 motorway at Great Lumley near Durham. It was pretty much like broomgrove but the holds are bigger. 4m high, 50-60m long and totally dry. Its around 20 named and graded up lines and umpteen traverses plus two aretes and a finger crack up the central expansion joint.
Me and John Boyle spent the whole of my summer there in 85 doing all the problems before another climber spotted us on his way back to work. Before too long it was really popular and the NMC even had a couple of wednesday night meets there. I think i have a topo of it i wrote at my folks somewhere.
Anyone who has driven up the A1 north of Durham has driven over it. Still worth a visit now and right next to a great pub.