Where to get body parts for F20


I'm a new member but a long time F20 owner (20years) which is unfortunately suffering from the rust bug having lived most of its life in the French Alps where they shovel tons of salt on the road in winter. What I particularly need are doors front and the rear split ones, also is it possible to get side box sections? This car is brilliant in a ski resort seating six people and goes anywhere, nothing stops it, so I'm very reluctant to give up on it.
Many thanks