Question: Who used the Reece-Fish carburettor?

Context paragraphs:
Carburetor heat: Carburetor, carburettor, carburator, carburettor heat (usually abbreviated to 'carb heat') is a system used in automobile and piston-powered light aircraft engines to prevent or clear carburetor icing.  It consists of a moveable flap which draws hot air into the engine intake.  The air is drawn from the heat stove, a metal plate around the (very hot) exhaust manifold.

Mini: The Mini is a small economy car produced by the English based British Motor Corporation (BMC) and its successors from 1959 until 2000.  The original is considered an icon of 1960s British popular culture.  Its space-saving transverse engine front-wheel drive layout – allowing 80 percent of the area of the car's floorpan to be used for passengers and luggage – influenced a generation of car makers.  In 1999 the Mini was voted the second most influential car of the 20th century, behind the Ford Model T, and ahead of the Citroën DS and Volkswagen Beetle.

Reece Fish Carburettor: The Reece-Fish carburettor was a carburettor used by Mini Se7en racers in the 60s and 70s.

D-400 engine: The D-400 series engine or the Iron Horse engine was a light-duty two-stroke engine used for powering lawnmowers produced in the 1960s to the early 1980s.  D-400 engines were single-cylinder engines designed and manufactured by the Outboard Marine Corporation (OMC; Johnson and Evinrude) for Lawn-Boy and Masport.  The D-400 engines displaced 109 cc, generated 2.61 kW of power, and operated in the range of 2400-3300 RPM.  The engines have a distinctive rectangular cowling that has created a nickname of Brick-top mowers.  Another distinctive feature is the two-finger vertical recoil starter.  The kidney-shaped muffler and exhaust unit is mounted beneath the mowers' deck and gives the engine a small, low profile design when compared to the newer and more powerful lawnmower engines.  The ignition system employs a magneto, points, and a condenser (capacitor) set-up with an unusual spark-advance system which utilised a weight on the crankshaft to adjust the spark-advance amount depending on engine speed.  The sprung governor was also unusual with a throw-yoke which operated under the flywheel and was linked to the throttle.  The carburettor was a float design and fed into a pair of reed valves.

Supporting paragraphs: Reece Fish Carburettor Mini
Answer: Mini