In reply to franhammond92:
Inside of the prow at Wilton 1 is probably your best bet I would have thought, as it faces south west and there is certainly a lot less scope for run off than most other places I can think of. Another option is Brownstones which is again south west facing but bouldering only, with plenty of scope for seepage. You might be ok at Denham, but I certainly wouldn't get up early if you go there as it has a general north westerly aspect. We don't tend to get much snow around here, slight sprinkling over night for instance, but general seepage from damp can often be a problem in winter.