Woohoo! You rock, Gerhard. That's inspired. I'm sure I can sort this out now. Both you and Tim have been an enormous help.
Cheers, Al. (Oh, and Tim: tip noted. I feel bad about not posting complete code- I do normally (not in python), but can't for this one. Thanks for wading your way through it anyway.) -- http://mail.python.org/mailman/listinfo/python-list
