Squadgy
To use a Private CofA aircraft for the initial award (to yourself) of a License or a Rating, you have to own it outright (100% share).
The bit about not paying the instructor anything I've read about but personally I wouldn't do it. Some people suggest a way around it is to charge say £3000 for the ground school. Do you know of people who have done this openly? Even if the instructor isn't paid, the examiner's (who for the IMCR can be the same person) name will appear on the app form which goes to the CAA, and in your logbook.
He would have to be a trusted friend, I think.