There is a loose rock high on the right side wall of the rising traverse climb chamber on floor 1 in Rhiwbach.
(as you are looking at the climb towards the window, look high and right half way along the chamber wall to your right)
I have raised a maintenance ticket to have it removed. However, it is very high on the wall, and whilst not very big, will be difficult to remove safely.
I will send another mail out when the work is complete.
Go Below Underground Adventures Ltd.