Hi all
Thanks for all the comments - I've been away for a few days and
haven't had chance to reply. You've given me some useful things to be
researching a little further.

I did know about the Park clamps but wasn't sure if you could get them
separately over this side of the pond. And it may well be true that a
rotating clamp is not as useful as I'd like to imagine it is. I'm
going to chase sown the scaff pole and also the padded plywood
approach. A nice 'getting-towards'winter' project...

Thanks again
J^n