I climbed a new problem here last week.
Culpeper's Practice is about 7c, and is on Nod's Buttress, which is found towards the right end of the crag, before you reach Woz's problems. Nod's Buttress is a big slabby wall with a long roof running along it's base, and has a distinctive smooth side wall with two diagonal cracks running up it. The buttress' left arete from sitting is mentioned in Ru's guide at 6b and is excellent. Culpeper's Practice climbs the roof and wall a couple of metres right of this.
The roof has an obvious juggy rail running through it, taken by a good looking E1 of Bonjoy's. For Culpeper's Practice, start by reaching the flake at the lower left end of the rail, and work up and left on crimps then slopers, making for a large, shallow, open scoop in the middle of the slab. once there, finish more easily up the slab above to the large break of Holly Tree Traverse.