The GPM is bollox
One of the duties CSD's get paid for is to hand out, and receive back, GPM's.
I recently witnessed a CSD give one of these to the child of a staff member, for the child to fill out. (the parent did not know about it).
Says it all really.......surely BA could invest in a post-flight survey emailed to the address of the person who did the booking, it is after all 2009. Although BASSA thinks its the 1970's.
BASSA = British Airways SENIOR Stewards (and Stewardesses) Association.