I joined last year as a DEP on the Airbus.
I spent over 2 years in the hold pool, no one in that time was offered a position on any type depite being told at interview it would be 777 or 744.
Even during the 2 years in the pool we got regular letters confirming 777 or 744, then after 1.5 years we (about 90 DEPs) were deemed to have 'time expired' and invited down to an 'update interview' during which we were told this is 'pass and fail' (lovely!).... they were out then to see who would accept shorthaul ....
I have friends who were 'failed' at that point, after having passed the full selection and put 1.5 years of their life on hold whilst in the pool .....
At the end of the day it doesnt matter what you fly in BA ... ALL THAT MATTERS IS SENIORITY !!!! TAKE THE FIRST TYPE THEY OFFER YOU ..... you can always change types latter .....
You will earn more and have greater control over your lifestyle on the expanding Airbus fleet than you ever will as a DEP on the 744 at the bottom of the list .......