Ok well I have a set calipers in reasonable-good condition, but the reason they are spare is 6 of the 8 pistons have corrosion/pitting that is either right on the edge of the piston or further down along where brake seal, seals against. But as you already have a set of calipers you should be able to make up a working set of calipers & pistons.
Unfortunately I am no where near Stoke, so they would have to be posted. Drop me a PM and I will take some pics for you etc.