Hi Donnie, have the same car and I have also had an intermittent problem with my gear box. There are a couple of things to consider.
1- is there enough transmission oil in the gear box, if not the pump can't change gear.
2- the gear box pump is linked to the drivers door and everytime you are entering the car you should hear a small humming sound, this is your pump priming itself, if you don't hear it this could be caused by a few issues. The pump relay is stuck and needs replaced(most common cause) or the pump is faulty.
However
Seen as your having issues with you boot lock too have you checked the fuse box in case something untoward has happend and blown a few important fuses.
On another note I live in fraserburgh and have a friend here who used to work for fiat as a diagnostic engineer and he would probably look at it for you if all else fails.
Let me know how you get on mate
Boydie