Central Locking Problems Forcing Sport & Manual Mode and Limp Mode

I have a 2002 discovery 2 TD5. Can anybody advise me on the following strange scenario:

But the battery is new, and terminals pristine. It seems as if there is a timer that expires after the car has been left unlocked for a few minutes, and that this forces the limp mode.

Is there a second battery somewhere that keeps some lox voltage computer systems running while the car is not in use?

The car works beautifully; it only has 139,000 km, has hardly been off the road, however, when we parked the car, and get out of the vehicle without locking it, it will either not start.

This is not a big problem; it is simply inconvenient because I discovered a way to "life hack" the problem by following the procedure described below:

(1) Lock the doors

(2) Unlock the doors

(3) Open the drivers' door (pretend to be getting back in the car )

(4) close the door

(5) Start the Disco

Then there are never any other problems.

Interestingly, if you skip this step (3) Open the drivers door (pretend to be getting back in the car), and simply lock then unlock the doors then the vehicle will start, but only in safety / crawl mode where the "S" and "M" lights are flashing, and the vehicle can be driven in crawl mode.

Has anyone seen this? If so, do you have any suggestions for a better workaround?