|Turning my attention to the boot of the car was a similar experience.
At first glance, the interior had survived pretty well considering it's age.
Looking down at the sides of the boot where the rear wings join on (I had to use a mirror to do this), I could see lots of rust. This was fully treated straight away to stop it coming back.
I then used several thick coats of hammerite rust treatment, and a couple coats of primer. This will no-doubt get painted over with lots of coats of higher-grade primer when I take the car to be re-sprayed.