Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,151 pages of information and 233,681 images on early companies, their products and the people who designed and built them.
1944 Prototypes of the design were trialled
1945 Production, also by Pye, ran from 1945 until 1966
When the WS42 was eventually cancelled (apparently due to being overweight) the WS62 naturally filled the gap.