Camouflage works, especially against trees as does terrain screening.
Harsh manouvres don't unless to evade an in progress specific attack due to sun glinting off the rotors.
A helicopter matching speed and direction of a motor vehicle is difficult to find with a doplar radar. So a Wessex doing 60 kts adjacent to a HGV travelling up the A66 could not be found by three Tornado F3 tasked to kill it.
Jets v heli 1v1 is fair, 2v1 not so fair, and a coordinated 3v1 is death waiting to happen.
There was a time when it was assumed a missile would not be wasted on a helicopter. Recent conflict suggests otherwise. It was widely believed that it would be a spontaneous guns attack on a target of opportunity without a second pass. However the Luftwaffe Alpha Jets were specifically trained as anti-Hind helicopter killers.
A helicopter crew efficiently watching his six is great, until the attack comes from above. There are never enough eyes out of the helicopter.
It was once trialled that helicopters carrying USL on a Brigade move would stop and (low) hover if attacked with the option to jettison and run if necessary. I believe this concept was never subsequently adopted as an SOP.