Thank you very much for your detailed answers.
So upon study of Boilermaker1's photos 2 & 3, it appears that the roof line of the depot building is slightly above that of the extended platform. The roofs of these two sub-structures appear to be separate pieces of plastic. If this is the case and the dormers can be easily left off, then I will se if I can find one of these kits to create a BR CB&N depot !
THANKS again for all of your help. I really appreciate it ! Have a great week !