It was quite common "in the day" to fit Fiesta calipers to Mini hubs as a cheaper way to get better brakes than going for more exotic sources or fitting (relatively expensive) Cooper S size calipers to allow fitment of 10" wheels.

I'm not sure if that is what you have pictured there, but the suggestions of a Ford type part would seem to fit the look and feel of what you have there.

Phil.

edited to add: I should actually look at the image before typing lol !! Looks very similar to those fitted to the Honda Jazz, including the pig-tail spring on the handbrake mechanism. Honda has persisted with thid (not very good) disc handbrake mechanism - I remember the 1984 Honda Prelude I owned for a while had a shocking handbrake mechanism which looked the same, and the aforementioned Jazz shares the same problems.

Pads picked up from Eurocarparts today & yes ford cosworth are a perfect match

What I said

Neil