On this coupe seat cloth, and I guess with any this age will be the same you have to release it from 2 clips and about 4 spikes that are hidden, I couldn't see the first 2, so if it wont peal back gently over the foam then there is still a spikey stabby thing holding it.
Again careful and these are the only things that hold that cloth onto the frame.
Pull the material out of this clip, one each side
Cloth out and spike hiding to the left, gently straighten them out
Spikey stabby bstd to the right of the clip
Hiding just to the right of the screwdriver
Back by the hinge the rear of the cover is held on with this soft listing wire tucked in as seen. Gently straighten it out and pull out the frame.
And you should be able to lift the foam and cloth off the base.
The cloth is still attached to the foam at the moment, DONT TRY AND PULL IT OFF YET
