The helicopters featured in the documentary do have an auto hover system fitted to them. It is fitted to make life easier for the winch op, so the aircraft stays stable at the selected height, not to stop the helicopter colliding with anything.
It is a very good system (louis Newmark), which is controlled by radio altimeter inputs.
The helicopters featured are owned by Bristow Helicopters, under contract to the coastguard.
I totally agree with all the comments about the pilots and winchmen. They should all get medals.