Hi Peter,
Thanks very much for your message. I'm afraid I don't have the Suntrekker any more and I'm not sure I can be of much help but, yeah, those aluminium back doors are a real pain aren't they? I managed to reduce the condensation problem by double-glazing both bits of the door with sheets of acrylic plastic from B&Q. While experimenting I just stuck them in place with gaffer tape but, had we kept the camper, I probably would have worked out a more permanent and attractive way of fixing them. It was a reasonably successful job - we didn't get the huge build-up of condensation on the glass, and it was noticably warmer, but inevitably we still got condensation on the aluminium frame. It just makes a perfect bridge to the cold air outside. I did contemplate completely dismantling the door (pretty easy to do with just two screws at each corner, as I recall) so that I could try filling the aluminium profiles with expanding foam but, again, I never got around to doing it before we sold the camper.

The biggest problem we faced with our door was that the nylon washers in the hinges had worn out so that the door sagged, causing it to snag at the bottom and leak at the top. Needless to say, I couldn't find matching aluminium hinges anywhere but I did manage to get all-nylon hinges, almost the same size, from www.isaaclord.co.uk. I just had to remove a very small bit of ali profile to get them to fit but they made excellent replacements and completely sorted that problem. As I recall I also attempted to limit the possibility of further leakage by sticking a length of Fiamma Drip Stop (http://www.agentfiamma.co.uk/fiamma-drip-stop-300-75.html) above the door.

Apart from that, I don't recall that we ever had major problems with leaks around the door unless the rain was really blowing directly at it in which case the rather pathetic 'felt' sealing strip against which the door closed was pretty ineffective. I think, as you say, the frame of the door is structural and so you're inevitably stuck with the square corners which makes replacement of the whole door quite difficult. Given that, I wonder if you might find something useful from www.sealsdirect.co.uk. They have the most amazing range of seals in every conceivable profile and there may well be something there which would give you an idea to pursue. I hope so.

Good luck. Regards, Martin