If you want to finish earlier before your Leave, have you rang crewing and asked for shift change they can be accommadating if you ask.
But we always start on an early after days off or leave and late before days off, thats how it works at Flybe.
As for finishing on a late and starting an early the following day this never happens, you always get your required legal rest time.
If things are so bad for you guys go and speak to your Base manager they will sort it out.