Whitey66’s (from tenere700.net) T700 quick release seat kit (now sold by Rally Raid) is a useful mod and saves fiddling around with a hex tool to get your main rider seat released. The only thing that bugged me was the two cotter pins (R clips) used to keep the two posts secure. They’re a pain to put on and a pain to take off and the small zip ties were annoying, too. I decided I could no longer be bothered with them after one of them twice bent out of shape when trying to release it. My fix was to cut two pieces off an old spring I had sitting round. Really easy to thread through the hole with one hand whilst pressing down on the seat with the other and it stays securely in place without a problem. A keyring would also work although that would probably be a tad more fiddly to put on. Any piece of wire wrapped round into a circle and overlapping by 10mm would work, though.
After some interaction with fellow group members on FaceBook, apparently there’s an easier way to sort this. I know I saw this months ago but being half senile I didn’t take full notice of it. It seems to work, however!