A very collectable engine. I cannot find production dates for the BV engines but a CAV injector listing gives a date period of 1952 to 1962. I would think production would have commenced well before this and ceased in the early 1960s. The injector of your engine has a cap with two flats. Early CAV injectors had a cap with a large hexagon. This makes me think your injector would belong to the later period of production, post mid 1950's. I understand the Anson Museum in the UK hold the Crossley records and the Internal Fire Museum would have manuals. Both can be found on the internet.
Hugh