I've pretty much got it running along the lines of your suggestion; I had a good peek at the SQL Access was generating and munged that into the Perl code. Because the query was itself nested I had to flatten that first... It's a tad uglier than I wanted (in its own way SQL can end up as unreadable as a good regex), but at least its doing what I want.

I did have a peek earlier to try and see if there was something in the links that would allow credentials to be defined there, but couldn't find anything. However, I didn't go as far as recreating links, and its always easier to look for something that you know exists, than for a possibility that might not. I'll go back and try that path - I never liked having to supply the credentials in any case, so embedding them in the links would be a plus all round.

Thanks for the pointers
Andrew