Here’s a new Clutch Master Cylinder (0.7") for the following models from MG -

MG

MG Midget Mk3 (1275cc)     (1966- 74)

MG Midget 1500cc               (Dec 74- 79)

(** There may be an adaptor fitted for the pipe to go in - You'll need to re-use the old one if it's fitted **)

The factory fitted Master Cylinder was all metal, this has a plastic reservoir as required by new regulations in order to make the fluid level more visible.