Thank you - that's what I wondered! Guess I'll bite the bullet and get stuck into the dismantling, then. So I wonder if the backrest can be swapped - I guess not, at least de-trimming it won't be hard if there are no horrible hog rings. Think the backrest centre is Velcro fastened? Dunno how to get headrests off!
What about just using some self-tap screws to hold those plastic bits on?
Well anyway, I've already had the bases apart this evening:
- fixed driver's outer bolster, had a flat top. I expected foam to be disintegrated but no, the slot in the foam had simply torn and sunk around the metal support rod. Easily fixed with duck tape lining the slot.
- the metal base is anatomically dished but, for some reason, the foam builds it up so far that it's just flat and firm. Feels like new but doesn't feel anatomical. I carved the foam underside flat, on the central squab. I used a new steak knife for this. I got the inspiration from someone who shared this on the forum. The modification doesn't change the appearance but it sinks when sat on
like a nice old saggy seat, it's just so much more satisfying. Hopefully despite being softer, the result will be more supportive because of being less flat.
Generally I think careful design and materials choice goes into car seats, like shoes, and it can't be improved upon by a backyard mechanic... But these particular seats really do seem like a design 'miss' - even with its added-on frame the front squab is way too short for average leg lengths, for example. In my yellow Spider I have removed the rear spacers and that definitely helps.
I learned that even if you clean the gaps between centre and sides with a damp soapy sponge, when you take it apart there's a lovely quantity of food waste/other dirt/spilled coffee/green mould trapped in there! The sides of the squab are carefully covered in reversed leather (soft suede) that holds the juicy goodness.