Harry, this is the crap that Alan S is stating however there is a massive difference doing a little overtime occassionaly and being rostered 92 + hours month after month after month, while conducting operations that take you over massive time zone changes (which we didn't use to do as much).
Add to this factorisation on ULR flights then yes fatigue is a huge issue in this company.
I can count the number of times I did overtime each year, before their new policy, on the fingers of one hand.
Add to this, that when you have leave that is less than a total month, the company schedules you for almost a full month in what remains, contrary to what they promised when the nominal credit for leave was removed.