Seems like the consensus on this side of the pond is we haven’t a clue!! Maybe a home built effort that someone has used a few ideas from different manufacturers.
Perhaps someone on your side of the pond knows something?
Here’s the pictures of your chassis
Here is what Russell Anderson (Anderson CSK Supremo) said, “Don’t recognise this Ian, sure looks a bit of a mish/mash. No welded in steering, brake mounting. Home Brew then. Not Anderson”
Here is what Boyd Barrington said, ” I think this could well be a modified Spyda. We didn’t make two the same so it’s difficult to be certain, but we did do one (or more) with bolt in T at the front. The seat mounts would have been welded in to match my seat and the conversion to 125 mounts and an airbox(?) bracket are later mods I guess.