In reply to David Hooper:
Just got back from doing a quick recce in the Bwlch Penbarras area for a training session on Sunday.
Dug a couple of test pits, there are some serious layers going on! About 8 inches of slab on top of 18 inches of powder.
The only easy wasy up now is from the top or bottom car parks. I've been up a few times in the last fortnight for MRT stuff and I'm always surprised by the conditions!