Can't argue with any of that Scubi.

It does mean you need a camera with the capability for such photo-faffing, with the remote flash jiggery-pokery. I think it's worth flagging up that from what I've heard, infra red or radio flash remotes are much more reliable than those optical preflash things. I've heard a couple of people complain about the poor synchronisation on those.

Mind, you can get similar results at a lower cost. If you've not got a dslr, most digital compacts have a tripod thread, a manual exposure option and a self timer. Add a tripod and a torch or preferably a separate flashgun, then you've got all you need so long as you're prepared to go photographing the carvings at night.

Set the camera on the tripod, choose the longest exposure you can, with the narrowest apeture, and set it to self timer mode. Then when you've hit the button, wave the torch and/or manually fire the flash gun from the side.

I think that with uneven carved surfaces, this can get better results than a single remote side flash, as multiple flashes. from different distances and directions, can bring out all of the contours of the rock. Waving a torch is a bit more touch and go, but hey, if it's digital, you just delete and try again until you get a decent shot.

And, you know, it might be mildly heretical to suggest it, but just waiting for the right time of day can pay supreme dividends:
http://www.megalithomania.com/show/image/7513/Rathgeran+Lower.htm
If the light isn't right the first time you visit the stone, have a look around to try and figure out the optimum angle for the light, and try and get back there at the right time. If nowt else, it's a good excuse to go back :)

Hope you get some joy with it all Idwal. I'm looking forward to seeing pics of some of these stones. And I really know what you mean about the red painted ones. I saw some in Denmark and it just looks wrong.