Moodster has a good point. Thanks all for your comments. To be honest I had not even considered the possiblity of query paramters, which is very silly of me. But hey, it was late. Anway, I can now look at this again a bit later on.
I am constantly amazed and impressed with the good nature and high value of comments that come out of this site.

Regards,
Gerard
The caffeine addict (now sufficiently supplied).