Even though this thread is over a decade old, there's a book by C.N. Hill titled A Vertical Empire: History of the British Rocketry Programme, and I would assume that it contains info about rocket engines developed for the UK's space rockets. The prototype Hawker Sea Hawk jet fighter became the Hawker P.1072 after it was modified to have the Armstrong Siddeley Snarler liquid-fuel rocket motor installed in the tail, and when the P.1072 began flight tests in November 1950, the Snarler became the first ever British liquid-fuel rocket motor to fly.
Even though this thread is over a decade old, there's a book by C.N. Hill titled A Vertical Empire: History of the British Rocketry Programme, and I would assume that it contains info about rocket engines developed for the UK's space rockets.