the cover itself had a few holes from munching by insects, easily patched with soft leather and glue.
I didn't take any pictures of the seat being reassembled.
Several broken springs were replaced and as the mesh just under the seat cover which located the tops of the springs was rusted in places, modern spring supports were obtained and the upper ends of the main springs firmly located on them by hog rings.
This unfortunately meant that when all was assembled, the seat was about 1" too high and I was perched uncomfortably and very high up. When the original seat cover was fitted over the top, I pulled it down too hard (twice!) to try to lower it - but the old leather came apart in my hands!
The solution was to tie the springs down (shorten them) by loops of very strong inextensible string. Fortunately, a brand new (albeit red) cover appeared on eBay, was duly won and fitted with more care.
The first attempt proved to still be too high at the rear and had to be dismantled to shorten the restraining strings. The cushion height should end up at around 8" at the front and just 4" at the rear.
When the cover was pulled down this time, it was quickly secured with a heavy duty staple gun and of course will take much of the load off the strings.
That's much better - two new covers produced locally for £60 each - and fitted over the repaired spring bases - perfect!