It belongs, or belonged to to an owner in this club. The link is below and is well worth a read throughout the whole of the post.
https://forum.mx5oc.co.uk/t/meet-monty/126751
The comment from the owner in Nov '22 is especially interesting
The car came back from rust protection and with very sad news to me, the previous owner masked the sills issue by amending only the external bit and it now needs “everything replaced” (not immediately, not structural, nor MOT failure, but still, the sooner the better). North of 3k… But, doing it next year. I had too many cars I didn’t really enjoy driving/caring, to know that if I give up and buy a new one I will only have to replace everything else again…