In reply to Simon Pelly:
I got one years ago from Bernie's cafe in Ingleton, made for caving so I just added gear loops. It's not 'rated' but then it doesn't need to be, your Croll clips to your harness, chest harness only holds you upright. It's tough enough it wont rip off in a fall.
IIRC Blackdiamond do/did one and I would be surprised if Metolius and Pika don't do something similar.
Croll isn't much use on a big wall (assuming you plan to aid, not just jug the haul line), you really want a pair of handled jammers.
jk