In reply to TobyA:
> (In reply to Franco Cookson) You could put a bolt in the holes! More seriously, even the tiny tricams wouldn't fit in a bolt hole I don't think, they are used in shot holes (drilled for putting explosive charges down and much, much bigger).
I have a small tricam that nearly fits in the hole and I know there are some camp things that are smaller, so maybe there's something that fits. I haven't measure the holes, but they're third finger sized- perhaps around 8mm.
I'm genuinely surprised by the excellent response- some good ideas there, although most of the solutions don't seem very good with outward force, which could be a problem with an overhanging wall. The other issue is that I need all but one hole for hand holds, so which ever solution I chose needs to be bomber by it's self.
Does anyone fancy lending me a removable cam.....?