Hi Chris,
I've just finished the door seals on a Jaguar (sorry) and I first rubbed them in with Vaseline.
I think the best option is to do this and to try to close the door on the next 'click' and leave it to stand for a couple of weeks (after 15 years maybe you still have some patience left).
On my Jag, after a couple of weeks or months, it became easier to close the door. At first, I didn't manage to open or close it because of the tension but after a while, time, pressure and Vaseline seem to have done the job.
Good luck!
Didier