Does it necessarily mean that if you are 737 rated you will be earmarked for the 737 fleet? If thats the case then it may be a plausible factor for the lengthy swim in the hold pool? With only 19 aircraft, it's BA's smallest fleet.
I do know a few guys that went directly to the 744 as DEPs. They all had been 737 rated, however it appeared to me that they were filling a void after BA realised that they were unable to fulfil their rated DEP requirements for that fleet. Would that be true?