Words in the July 2011 issue of Motor Sport

[Markus Berzborn]

I think Bristol would have done this within the limits of their possibilities if you had asked them.
For instance the body panels of the Blenheim 4 discussed here in the forum also largely differ from the standard model. Or look at the Speedster/Roadster.

And it's much easier to do on a separate chassis than with a monocoque construction.
In fact this was standard practice for luxury car manufacturers before World War II.

Regards,
Markus