Martin, I have a few 35mm 'trannies' of the now lost BAe T111 (basically the same as the FBVI), but I need to get my tranny scanner back from a friend, so can't promise when I can scan them.
However, having been in two Mossies, and having the honour and privilege of knowing a number of Mossie crews, I can state that the pilot's seat was definitely a bucket for the 'chute.
Problem with companies taking patterns off preserved aircraft is that they tend to replicate exactly what they see - and of course, those preserved Mossies will normally have some form of cushioin to fill the bucket, otherwise people couldn't sit on the seat!
Bottom line - bin the cushion, and leave the seat pan empty !