Major leak major electrical issues

Hi all first post on here thanks for allowing.
So I have inherited a 2008 td4 freelander 2 that’s been sat for 2 years. I opened the drivers door only to be welcomed by 4 inches of water in drivers foot well. I’m fully aware of the usual leaking sun roof drains and air con etc. however the plot thickens…..
I have some major electrical issues. No crank. Hdc fault. Transmission fault. Crash comes up. Something has obviously got wet. But before I start pulling things to pieces. Is there any ecu behind dash or glove box. Any help welcomed. Thanks. Nick.

All of those warnings are related to a failed battery, the CRASH status is set if the battery voltage suddenly drops to below 8 Volts, which can happen if a start is attempted on a flat battery. Only LR specific software can remove the CRASH status from the systems.
The other issues only come up if the battery voltage is low when cranking.

There are some 30 modules in this vehicle, no modules on the driver's (assuming RHD) floor, but the sat nav is under the driver's seat.
The CJB and fuse box are behind the glove box, several inches above the floor, so should be OK.

The leak could be from several places, often the scuttle drains can block, allowing water to get into the cabin.

Hi there. Thanks for reply mate.
Ok so first things first I’ll grab a battery tomorrow and see what happens.
When I first went to the car last weekend. I connected the battery and started instantly. Then the horn started going off randomly and I turned the car off while I found the horn fuse to pull to save angry neighbours!! Then wouldn’t start after that. Just said steering column locked. (It wasn’t). Today I go to the car with a trailer and winch this time. And everything happened as described in first post. However steering column was not a problem. I had to manually mover the gear selector as I couldn’t get out of park! Could this also be a battery issue. Thanks again nick.