Old Style Brake Setup

Hi all
I have an old Tony Kart Esprit and am struggling with brake parts. Managed to get caliper seals ok but the replacement seals I ordered for the master cylinder are too small and no others seem available here in the UK. Has anyone fitted a newer type OTK master cylinder to this setup, would it work with the original caliper? Pics below…

wait…I’m doing the same restoration on a similar chassis, let me take a look in the evening…can you tell me the inside diameter of the master cylinder so I can compare with mine?

Thanks for the reply, I won’t have the master cylinder to hand for a couple of days to measure. The new seals I got are just slightly smaller diameter and are loose in the housing,I’m wondering if I fitted the new type pistons, maybe they are bigger and stretch the seal out a little more :thinking: might be cheaper to buy a s/hand new type cylinder if it would suit the caliper :thinking: