ayahhhh
Just finished the job....
10mm ratchet spanner/wrench is a must have - a regular ring would be painfully slow and there's no room for a socket. Slide the seat all the way forwards, undo the back bolts. Slide it all the way back and do the front. Lift the seat out - it's heavy!
I created an "n" shape which I put along the front edge of the seat spring with the arms going down either side of the seat, about 1/3 - 1/2 way back. This is inside the springs and the runners rather than between the leather and the frame. Then I cut (saw) a second piece of noodle and put that along the front edge behind/under? the top of my "n". This is at a narrower part of the spring mechanism so to stop it popping out, I used 4 cable ties to secure it.
Seat on the mounts, faff around a bit getting the bolts in place and off you go with the 10mm spanner. Fronts, then backs.
It does make a difference to the seat - I am a little higher up in the car which some may not like/need (and I am 188cm) but the support under the thighs is so much better than previously. My seats were restored in the 1990s so are not in bad shape but as a chap of some mass, find the extra support useful!
I thought about the Mechatronik seats (I sat in Tom Sargents car in Alsace) but they are higher again which put me off a bit.... and a pool noodle was a couple of quid (each) on Amazon
Sorry, must take pics next time