My son, who is 15 and has an encyclopedic knowledge of railroading, made an interesting observation about the old black and white photo.
He was able to tighten up the date a little bit. He noticed there are 2 tenders. The second is a water tender. This was added after Alan Pegler purchased it in 1963, the reason being that when steam service was discontinued, all the water columns were taken out and the Flying Scotsman needed to provide her own water.
So, he disputes the claim that this photo is of regular service. It would have been post private purchase by Alan Pegler which occurred in 1963, but before the voyage to the States in 1969.
This kid had a 4 hour, multi-disc documentary on the Flying Scotsman that he used to watch obsessively when he was about 11 years old. We've given him his own room in the house just for setting up a giant model railroad and he stores his massive collection of model trains and railroad memorabilia in there. He has an equally massive collection of railroad knowledge in his head. He truly is a railfan-atic.