Thank you all so very very much! I am now going to look at all the research you have so kindly found- and remove all the dross to pick my way through it all!!!
Have just come back from 2 hours on my feet collecting for charity so will enjoy an excuse to sit down!
Hopefully now I can come up with a definitive answer- which I will post -and then mark this thread as Complete! Fingers crossed- and once again- many many thanks!
caroline
