There is a High court hearing soon between J2 and Balpa regarding "rostering". If they really are losing a lot of crew and roster patterns/lifestyle are part of the issue, it all seems a bit odd.
Balpa maintain that this is part of Pay, Working Hours, and Holidays scope, and the company should negotiate with it about pilots rosters. J2 disagree and a High court hearing will decide the matter.
12 employment cases for 2015- Publications - Eversheds International