@Adrian Norman said:
I’m interested in the five locos allocated to the GE area. Two questions : … were they delivered in lined black in 1951. The published Dr Ian Allan photos are ambiguous, was it just that Cambridge depot kept them grubby?
I have no idea about the answer to your question. It’s about four decades after my period of modelling interest.
However, I am a member of the GER Society, and will ask the question on their e-list for you. Hopefully, I’ll be back with an answer soon.