On the 3rd pitch (as given by UKC/Rockfax), at the end of the ledge before the hand traverse there's a large detached block. Given the chalk it looks like the block is well used. As I was pulling on it the block clearly moved outwards - maybe it just rocked over, I'm not sure - it definitely freaked me out though! I think it's stable in it's current position, but it's directly above the 2nd belay (also an ab point), the top of the 2nd pitch and the area where people tend to gear up on the ground. I'd definitely be very cautious if I was heading up there again.
Thought it was worth posting on here. Also reported to the BMC Access Officer for Wales.