"The Setmakers" is a sad story of the decline of the UK radio and TV industry. It's an important reference book for anyone interested in the UK industry. Copies readily available at fair prices in the UK:
https://www.amazon.co.uk/Setmakers-H.../dp/0951704206
The unique 405 line standard kept foreign competition out of the UK market for many years.
Coming back to Pye and their post WW2 TVs. The B16T/D16T was the first new TV made in the UK after WW2 in 1946. Mains EHT, nice compact chassis. Capable of very good pictures. The BBC modified them to use as low cost video monitors. They were followed by the B18T/D18T in 1949 which was the first UK design to use flyback EHT.
The FV1 was a couple of generations later by which time better valves were available and designs were starting to look more standard.
The V4 etc which followed the FV1 was quite a complex set, designed for quality. Its LOPT (flyback) is problematic.
http://www.thevalvepage.com/tvmanu/pye/body_pye.htm
The Thorn 2000 series (nothing to do with EMI at that time) was their first colour set sold under various brand names. It was the world's first fully solid state colour TV. Launched for the start of colour TV in the UK. I'm restoring one at the moment.