Let's see...
...yep, that seems do have done the trick. Thanks for posting the other pic, Clive. Gives me the jitters to see it as it looked before I started tidying it up. Beneath that stunning and deceptive surface lurks two full bin bags of damp sound proofing, tons of cables and a blown boom box in the boot, trail ignition circuit 60 degrees off the mark, etc, etc...
Now, after getting rid of the rust in the rear, the paintwork has become two-tone. That colour (burnt orange) doesn't age too well. It goes brown-ish, so the rest of the car needs doing next. Currently stripping down doors and front end for the return to the paint shop.
