F***ing hell - sorry Russ and Gerry - I just managed to delete my last post (which you've just quoted). How do I put it back?
EDIT: Bollocks to it - here it is:
Thanks guys - interesting stuff.
FWIW - This is what I've picked out of it all
1) If your grounding is spot on then ground BOTH ends of your shield.
2) If your grounding is not spot on then grounding both ends is likely to introduce earth loops so just do one end.
3) but in the real world it's not that easy so if it doesn't work then do something else.
But after all this I'm back at my original question which was why commercial ready made up cables have the shield connected at both ends. I guess it's either that or just one end so the designer tossed a coin and said - two it is