Here's a Clutch Master Cylinder Repair Kit (5/8") for the following models from Triumph -

TRIUMPH

Triumph Spitfire Mk1

(1962-65) (Brake or Clutch)
 

Triumph Spitfire Mk2

(1966-67) (Brake or Clutch)
 

Triumph Spitfire Mk3

(1967-70) (Brake or Clutch)
 

Triumph Spitfire MkIV

(1970-74) (Brake -Single System or Clutch Master)
 

Triumph Spitfire 1500

(1974-77) (Brake -Single System)
 

Triumph Spitfire 1500

(1974-81) (Clutch Only)