This German website has a surprisingly detailed history and factsheet on every Bristol model, including the 450 and Fighter. The following links are to the 400:
and the translation link is:
To see details of the other models, either
1.Delete the model number in the link to the German version above and substitute the required model number, then click the link.
2. In the translation version, substitute the model number in the search box and click ‘Search ‘.