Back at the beginning of this thread richsprint mentioned Biggred.co.uk
They are based in worcester and are very knowledgeable.
I bought a pair of reconditioned 7th gen tourer rear calipers, not including hangers for £139. With the option of sending my orginal calipers back to them for a £40 refund. That makes it £99 for the pair.
The recon includes new parts: pistons, inner and outer seals, Bleed nipples, protective caps and the bellows for the sliders.
But to start with they shot blast the caliper body and re - electro plate them.