Both Bristol Commercial Vehicles and Bristol Cars emanated from the same stable "The Bristol Tramways and Carriage Company" which, in 1910, began building aeroplanes and the diversification meant that Bristol Commercial Vehicles (BCV) was eventually (in 1943) created as a spin-off of the Tramways company. BCV later became a subsidiary of the British Transport Commission and in 1965 became closely tied to ECW (Eastern Coachworks) and Leyland as Leyland had bought shares in both. The factory closed in 1983 as commercial vehicle production was consolidated into other Leyland units.
In 1945 the Bristol Aeroplane Company created a car division which became Bristol Cars. This was later separated from the parent company when that became part of The British Aircraft Corporation.
So the Bristol name is used here generically as there was little connection between these companies products except their organisational heritage.