indent Another uniquely Great Western branch line sight was the two coach "B Set".  Less commonly known is that an "A Set" was originally a single composite coach - usually a brake compo - while a "D Set" was a four-coach set of non-corridor brake third, third, compo and brake third.  (A "C Set" may have existed but I've never seen a photo of one - unless you know better...)  These alpha set descriptions were common only on "Working Time Tables" where they enabled the make up of trains to be pre-determined without mentioning specific vehicles.
indent It could be argued that because the B set is a permanently-coupled pair it is not ideal from the operator's point of view because the train's make up cannot be changed.   While this is true it is not only prototypical but a B set does make an attractive train aesthetically, even if they were less common than "scratch sets".  Why Hornby or Bachmann do not make more typical branch/local stock for the Great Western I do not understand -  a few carefully-chosen non-corridor clerestories or some non-clerestory, non-corridor bogie stock - or even some accurate arc-roofed 4-wheelers - would surely be extremely popular with any GW modeller because of the added flexibility such stock would give to train make-up.  But I'm having a moan...

indent The original RTR (Ready To Run) model of this coach was made by Airfix over 20 years ago and has appeared regularly on GWR model layouts ever since.  The currently available model is made by Hornby, as we have used here. 
indent The most notable changes we have made to the standard model have been to a) paint the bolection mouldings red (these are the "drop light frames" around the windows in the doors), and b) to remove the standard couplings and buffers from between the vehicles and replace them with a close-coupling bar made from an off-cut of plastic card.  This semi-permanently couples the vehicles together which was precisely what was done on the real B sets.   Of course we have also c) repainted the roofs to replace the white lead with a dull, well-weathered grey/brown (it is wartime!), and d) re-painted the chassis/bogies with a varigated muddy brown reflecting the "dirt and brakedust" colours you can see if you look at any real coach chassis today.