Martyn, that is a terrible situation you have found yourself in.
Lately I believe, BA has been sending out a number of Volunteer Crew on scheduled flights to keep in safety check in event of keeping BA flying during possible future strike action. Someone pointed out they are from all departments including Check-in, Ramp Services, Dispatch amongst others.
With the sheer volume of cancelled flights that would mean hundreds of valuable staff are stranded abroad when in fact they could have been at T5 assisting to clear up some of this mess. An outrage.