Early British Railways Loco Livery

[PatB]

I'm currently building a Connoisseur Y7 which is to be finished as British Railways 68089, one of the class which worked on the North Sunderland Railway.  It's almost time to start applying paint and I've just realised that I'm ignorant of the details of early British Railways black with BRITISH RAILWAYS lettered on the tank sides.

 

Firstly, what colour would the cab roof be?  Perhaps more accurately, what colour would it start out before soot and weather?  I'm assuming the same black as the rest of the loco but it occurred to me that it might be grey.

 

Secondly, would the buffer beams be red?  They look like they might be in the photos in Alan Wright's book on the line but if anyone could provide confirmation it would be helpful.  Also, in at least one of the photos, 68089 appears to carry her number on her front buffer beam.  Would this be in gold, yellow or white?

 

I've been imagining the safety valves and whistle to be in bare brass, but again, I'm not sure whether this would actually be the case in days of post-war austerity.

 

Any help or advice would be greatly appreciated.