TL MOT failure!

My new Touring Limousine failed at the MOT! Left side rear brake did not work at all, but the right side had 2kN braking force. So I had to open up the brake, one piston was completely jammed, and the cylinder was leaking on the other end because some corrosion and hardened rubber seals. These original wheel cylinders are 22mm, but the local parts shop is only offering 23,8mm cylinder from 1302 front brakes as a replacement. So I need to replace both sides. Not a bad idea, as I bet they are decades old, if not totally original. I already made new pipes, put in left side hose & pipe and cleaned the internals, as the leak had gotten all wet. Now I just need the new cylinders, they should arrive within a day or two, as they needed to be ordered.