This is the clutch master cylinder from a 1966 Spitfire MKII, the same as the MKI and a 1965 Herald. I think the master cylinder was pretty much to same throughout production. I'm not sure about interchange of parts from Spits to TRs, though. Since many parts were used in early Spitfires, TR 4 & 6 I suppose it is possible. Clutch Master cylinders have one pipe out the only, unlike brake master cylinder is later cars.
T.T.