In reply to ClayClay: Thanks, will phone them tomorrow. Not liking the look of their "7 day turnaround" for orders though
Hopefully a telephone conversation will be more helpful than the website! Will do some more searching for the part with that number as well.
Mine is the aluminium pump, not the plastic one, so not sure if that makes a difference. I doubt it does as they are the same thread at the pump end I think (for gas cylinders).
Thanks, Martin