I believe most RR Dart powered aircraft used water/methanol injection to either restore or boost engine power in hot/high operations. The RR Dart Mk529 was an example of a restored power engine while the Mk532 was a boosted engine. The Fairchild/Fokker F-27 series of aircraft as well as the Gulfstream G159 used water meth injection.
From the Fairchild manual:
The Fairchild F-27 aircraft is equipped with a water/methanol system which provides maximum engine power without exceeding allowable turbine gas temperature when high ambient temperature necessitates fuel trimming.
When operating at high power settings in high ambient temperatures, fuel flow must be trimmed to maintain engine temperature within acceptable limits. To restore the power lost by trimming, a controlled flow of water/methanol mixture is automatically injected to increase the mass flow through the engine. Although an increase in mass flow could be obtained by using water alone, this would not restore all the power lost by trimming since engine temperature would be lowered.
By adding methanol to the water, engine temperature is raised to the correct level which, in conjunction with the increased mass flow, restores power lost by trimming. Thus, at sea level, with temperatures above ISA, engine power is restored to the value that would be obtained under ISA conditions. At altitudes above sea level, power is restored not to it's sea level value, but to the value which would be obtained at the particular altitude under ISA conditions by automatically correcting for pressure altitude. Power restoration takes place up to an altitude of 10,000 feet.
Gulfstream says essentially the same thing
The correct mixture for the above is critical. It is 63% +/- 1% of water and 37% +/- 1% of methanol by volume. W/M is extremely corrosive, so if you have to handle it personal protective devices are essential.