Hi thanks for using JustAnswer. It sounds as if your drivers door latch has failed, there are 2 ways the alarm system deactivates on your vechicle, first is with the remote on the key the 2nd is using the key in the drivers door. You also mentioned that the doors where unlocking/locking on there own while driving. This is another sign of a door latch failure. So you will need to have the drivers door latch replaced, this should take care of vechicle not starting and more than likly get your central locking system working again.
Let me know if you need anything clarifed or have other concerns just reply back and I will do what I can.
Dave
Land Rover Shopforeman
Land Rover Master Technican/ASE Master Technican. 12 years Land Rover Experience