Rear Wheel Brake Cylinder 7/8" Classic Mini Morris Minor Rover Austin Healey Sprite Mk1 GWC1114

Rear Wheel Brake Cylinder Rover Mini Morris  Austin Healey Sprite Mk1 (frogeye) GWC1114Z

Austin Healey Sprite Mk1 (frogeye) rear wheel slave cylinder. GWC1114Z

Brake Wheel Cylinder Diameter is described as 22.20mm or 7/8" bore
As typically found on the following cars:
Classic Mini
Austin Healey Sprite ( Frog Eye) 
Austin Healey Sprite - All models to VIN HAN6-20544 - Single Acting Piston type 1961 - 62
MG Midget - Mk1 models to VIN GAN1-13554 - Single Acting Piston type 1961 - 62
MGA
Rover Cars
Morris Minor 1953 - 62

Alternate part Numbers 
GWC1111

RBK105