Chair Repair

Im trying to reupholster an old office chair that I acquired when I finally moved out of my last student flat, and in to a flat with N (circa 2005).

The material I'm using is from 1967: some blue tweed from a skirt kit. The chair has an inspection sticker on it dated 1996. Not sure how old it really is, but I like that it's mainly metal rather than plastic.

My reupholstering is very much a hack job, on top of an old hack job. The screwheads on the base are all worn, so I'm not able to dismantle it properly.