Hi Folks,
Brilliant, I must be going senile ! The double equal sign was the problem. I assumed (obviously incorrectly) that snce I wagetting no reports of syntax errors that there could not be a mistake of that kind. Consequently I dd not check as well as I (hopefully will in future) My only regret now is that I don't live near enough to either of you Guys to buy a round ! I am extremely grateful. many thanks