I'm with crab on this one Nick.
Control the path on the glide slope with the collective. Especially so with a attitude retention system such as an un-coupled approach with an A/P equipped aircraft.
Also lets remember the Regulations re Speed restrictions. As a helicopter is classified as a Cat A for speeds, a Cat A speed range on final approach is 70 to 100 knots. This still allows for up to 150 knots on the intial and intermediate segments of the approach.