PA, how do you do it? You are an international treasure! Did you
a) already know it,
b) know where to find it or
c) find it from scratch?

Whichever way, the speed of response is very impressive. Thank you very much indeed- hope I can help you sometime.

Thanks LtS and Malcolm too- I knew that version and had found that link, but I'd had no luck finding the original version.

Noreen