This is the original MK1/2 shape with correct 1.25" small neck. Originally made by Winguard, these plastic washer bottles for early Mini's were often asked for, but rarely available.
The original Winguard MK1/2 bottle part number was ADA3833, now 17H2536.
The bracket for bottle is 37H9712ORIGINAL.
MK1 uses 2 wire clips, see 37H9672.
MK2 uses 1 bicycle wire type clip, see 24A1387.
A new stainless steel bracket to hold the bottle is also available as 37H9712.
A washer bottle with 2" neck and Tudor emblem as fitted to many Austin MG variants is available as GWW918 which has a non return valve on a hose for fitting in bottle.