New addition to the archive site: Roadtest Midas Gold coupe magazine Motor august 2 1986, 4 pages. files motor 0886 p26/27/28/29 in the gold coupe dir.
Yes they're not a light car. On the two I've owned there is much more variation in the thickness of the various panels than on the MK 2, the MK 2 is quite uniform in thickness and on the whole thicker. There are some really thin panels on a MK 3 in comparison.
My current MK 3 felt a good deal lighter than my 900kg ish Micra on the trailer when I towed it home.