Posting in a hurry before you leave for work is not advisable.
I am well aware of the 748, Andover and the J31 / 41 fleets. The ATP was an attempt to enter the 50-60 seater turbo prop market when props were suddenly the "new big idea". Taking the lineage and upgrading the basic airframe and systems was , however, an unmitigated disaster.
In terms on maintainability it was horrendous. A few examples :
O2 bottle could not be charged in-situ.
Air stairs retract button..located on the base of the fwd pax door.
Rear doors...shoot bolts frozen.
Nose u/c...at least two grease nipples impossible to access.
Retro-fitted access panels
All the L/E de-icing boots were unique to each aircraft...interchangeable ?....no chance.
Engine and airframe anti-ice controllers....both buried in the belly
I/c jack plug.....British type !
Flap track drive motor....replenishment cap was 5/16 Whit. !
Loganair had an IFSD from..Woodford to MAN.
Weight and balance...."tight" is the only word here.
Horizontal stab...vibration.
Galley. No ovens, only a Bev. maker.
Engine change....how many days did it take ?
Product support?
The aircraft was a heap of junk and the original operators got rid as soon as they could. BAe wanted a "name on the tail" I understand, so they got BM and BA at a generous discount so the rumour goes.
The 748 / J31/41 fleets were, to a degree, successful, certainly the former. The Andover was short lived in comparison and the ATP was never going to be anything other than an abomination.