Had a look at Stauff clamps, and think I have found a winner
Page 38 and 30 of this:
http://www.stauffang...EM%3d&tabid=662
Reveal these two clamps:
Either would do nicely IMHO, holding the wires securely, both are made out of plastic so shouldn't short if for instance the wire got badly snagged and pulled the insulation off at a clamp.
Will update with costs when I find them
Bish, cheers for the offer, think I am sorted in this case, but if I fail I'll find a piece of polypropylene or similar and give you a ring.