Neil, I'm afraid I don't have the answer. As a fellow 1980 4/4 4-seater owner, I can only offer sympathy.
As I posted here at the time (
Squirrels have eaten my hood! ) my 4/4 suffered a rodent attack in 2014. Mrs W and I did a fairly good job of patching up the holes in the fabric but ten years later the window seals still have their bitemarks. As you mention, the little b*ggers don't confine themselves to one small part but do their best to make a hole in every available panel.
I've just learned to live with it. I don't often use the hood anyway and without it, the sidescreen seals don't matter!
Good luck anyway.
