Regarding the engine, this is why I am starting to look for it now even if I do not plan to be ready to install it before at least 2 years and half. Wings, landing gear are common to all versions (Mk I, Mk II and III). The mk III, flown by J Webster during the 1931 King's Cup was with a Gipsy Major, a lot more easy to find. This is my backup plan
I will update this thread as I collect information and with project's progression.