They have to have somewhere to park all the idle 175s they bought....
ABZ is a declining market at the moment; still big but shrinking. The fields are mature and the oil companies there are more open minded than ever to share cost on helicopters. Why NHV think now is a good time to get in is anyone's guess. They've had a year almost to delay this, maybe contracts mean that they had to 'take delivery' of it but there are so many other places their money could be spent.
Surely that capital would have been better spent on the Ghana work they already are on or tendering for?