Thanks, if I've got that straight - the SRAM derailleur will work either way.

Seat tube is 31.8mm and I am looking for a clamp on but there doesn't seem to be a big selection of bottom pulls and like I said the ones I've seen, other than the SRAM, don't say if they are 7/8 or 9 speed. I think I'll just buy the SRAM and not worry about doing any more fishing around.