Hi Nigel
The thick washers for under the runners are much bigger, so not that. I had a good look and refit of the parts and concluded that I have no idea where these washers came from……. Maybe on the later Coupe seats I stripped.
The end result is that I am going with just the plastic washers on the inner side, then the tilt mechanism and finally the bolt with the countersunk washer.
Photo shows the bolt, countersunk washer, unknown thick washer and plastic washer.
Peter