@ST: you seem to understand the question is about "having a plane refurbished" i.e. by a specialised company, or several. I rather read, though, T/S considers doing at least a big part of the job himself, or at least under his own control.
If that be correct, I should think it can only be attempted with any chance of success on a few national registries: US, perhaps France. Others might be possible by re-classifying the plane as an experimental (G-reg Staggerwing?).
But you certainly will need to have the work inspected and approved by a person or an organisation duly qualified. Find one, and discuss with them, before buying anything!