Buster11,
What a wonderful record of your father's POW days ! And what a simple and ingenious way to smuggle information past the German censors - but I have to say that they must have had little training in, or experience of cryptography, to be taken in by such a basic ruse. Alone the fact that:
... My father wrote all his letters from prison camp in a very neat upper-case script about 1.5mm high...
instead of cursive script, which any educated man would be expected to use, should have alerted them at once - and that the British censor had to appeal to your mother for help does not inspire much confidence in their abilities, either.
The Long March west in the depths of a mid-European winter must have been a terrible affair. When I was on the ATC School at Shawbury, one of my fellow instructors had taken part in that March as a POW. He related how one chap was obliged to squat in the roadside snow to defecate, only to receive a volley of abuse and threats from a guard (or so he interpreted it). A friend more literate in German assured him that the guard only had his best interests at heart - he was warning of the danger of piles from contact with the snow ! (I do not know what medical basis there is for this).
The loss of his watercolours is a tragedy; I would have thought that any surviving ones should have an arrangement whereby they eventually find a home in the IWM. And I'm surprised that the USAAF C-47 which repatriated him made landfall in Cosford. I thought that Manston and East Anglian airfields were used for the purpose, as that enabled the "rescue" transports and bombers to make more trips in the day. Perhaps the C-47 was going on to (?) Burtonwood, and had picked him up "ad hoc" as they had room for a few more in the back.
All these are fascinating detais which flesh out the wonderful stories on this and other Threads.
Thank you, Buster11. Danny.