Complex sentence: During World War II, car production at Luton was suspended to allow Vauxhall to work on the new Churchill tank, taking it from specification to production in less than a year, and assembled there (as well as at other sites).
Split into simpler sentences: During World War II, car production at Luton was suspended to allow Vauxhall to work on the new Churchill tank. Being a record of the war-time activities of Vauxhall motors Ltd. pp.90--94 it was taken from specification to production in less than a year, and assembled there (as well as at other sites).