I'm finishing up the painting of the interior, inner wheel arches, the underside of the car, inner side of the bonnet etc. All this with polyester paint made for marine use which gives extra durability and will protect from moisture getting into the glass fiber.
Progress will continue to be slow over the next yeah as we have just bought a new house which will require a bit of TLC.
BTW: when I rebuild the frame i realised that most of the rust had come from the inside of the tubes and not from the outside as I would have thought. To protect against this from happening again, I have injected half a deciliter of oil into each tube and sealed it off. I have used oil made for outboard boat engines as this has the desired characteristics.