High Reynolds number tip leakage flow is examined in a variable pressure water tunnel for a range of incidences, gap heights, cavitation numbers and free-stream cavitation nuclei populations. Acoustic measurements alongside high-speed imaging capture the prevalence of cavitation which is shown to be complex and often intermittent. It is a product of the combined effects of the strength of the leakage flow and hence vortex strength, the nature of the nuclei population, and the relative thickness of the wall boundary layer to the tip gap clearance. Persistence of cavitation in the leakage vortex is sustained by three main influences. The event rate of new cavities, the duration for which a cavity can be sustained, and the speed at which an established cavity is advected downstream. These processes affect the character of the measured acoustic emissions. These vary from persistent to intermittent bursts of noise for which temporal and spectral analyses are required depending on flow conditions.