Just to clarify a couple of points:
The AFS have one vehicle (Fire 7) which initially attends incidents at the terminal prior to the arrival of Strathclyde tenders, at no time whilst Fire 7 is at the terminal is fire category reduced.
BAA have a contingency plan which involves off duty staff from other BAA airports manning the station at Glasgow and providing cover, this will probably result in a reduced fire category as I have no doubt that not all the tenders will be manned. This may result in problems for the likes of Emirates, however, it is possible that they can have an additional tender available for the arrival an departure of Cat 8 a/c and resuming cat7 thereafter.