Thanks tornadoken and Whispering Giant for the information.
I'm aware of a 1942 agreement between the US and UK dividing efforts towards transports (US) and bombers (UK) (although I haven't yet seen a copy) and of the 'Types' that followed the Brabazon Committee's report.
I was wondering about the fatigue issue, given the pre-Comet understanding of it. Thanks for the tip, tornadoken. The business of so many savvy people missing the mark completely about the future of air travel is very interesting. They were 180 deg out. The story of the other Types is interesting too. I'd called the Bristol Britannia a success in certain roles. I don't think the 170 Bristol Freighter was one of the 'Type' aircraft but they were very popular around Australia and NZ until relatively recently.
Anyway, thanks very much for the information. I knew Pprune would deliver!
I'll PM you, WG