As far as I Know the only Leonides Major installations were in the Handley Page Herald prototype, the Navy Westland Whirlwind Mk 7's and the two Queens Flight helicopters before they were turbine powered. I flew the last ex Navy Mk 7 which is now in the Helicopter Museum. Presumably all the engine manuals went there with the helicopter.
It was not my favourite engine/airframe combination as the engine had to work at high rpm all the time for which I am sure it it was never originally designed, the throttle/collective lever correlation was the worst I ever came across and the hydro mechanical clutch also contributed its share of unreliability problems. Before starting, a little crank inside the front cowling had to be turned 96 (!) times to turn the engine over to ensure no hydraulic locking.
Now prepared to be shot down by ex Navy Mk 7 drivers who will insist it was the bees knees and the queen of the skies.