I think pilots in their intial training and recurrent training there needs to be more emphasis on decision making, risk assesment through reading AAIB reports.
As mentioned before I think there is within parts of the rotary community a different attitude to pressing on in poor weather and many fixed wing pilots have a different attitude climb to MSA and or 180 degree turn and request radar, of course the latter is not an option in a valley.
While even the RAF at Valley were probably not flying and this flight was planning to fly go through Snowdonia was a CANP filed, that would be a sensible option. It concerns me that even if the conditions were flyable, that a Hawk or SAR rotary might be coming in the opposite direction.