You need to stop the water Comming in as it will, if it hasn't already cause havoc with the electronics or damage ECU's !
Traced that my water was getting through the tailgate rubber seal as it was old and shrunk
New seal fixed the problem
Water is also known to enter through the back side...
The fact they are all starting to play up would suggest the problem is not the actual door actuators
Have you checked the rear spare wheel area and amplifier area isn't damp from water Ingres ?
In any case
If your serious about owning an L322 and you can't afford to take it to the garage every time it breaks them I would highly recommend you invest in some of your own diagnostics equipment
It will pay for itself in next to no time. It's a must have for any L322 owner really !
The immobiliser might we'll have got confused / wiped by the low battery cranking you attempted
Id disconnect the battery and leave for 20 mins
Then re attach and try again
If not, you'll most likely need some diagnostics to sort
The RSW All comms has been designed purely for the range rover.
other readers that cover many models don't often have much functionality with the range rovers ECU modules
Cheapest way to calibrate the suspension yourself would be to get an All Comms device
This is a great bit of kit, will read and clear faults, calibrate your air suspension and more !
And will soon pay for its self after just a few uses
Sounds like an immobiliser issue
Might have to take it to a garage with diagnostics equipment
Brake pad warning won't be linked to this issue, but in any case your brake pads have worn very low so get them sorted asap