Have you googled? I gave you my guess. Here's another guess: fuse box.

 

The dealer gets the lion's share of the repair bill. Some goes to Land Rover for parts and various franchise fees, software upgrades, etc. Some goes to retire the debt on that swanky building. Parts manager and team has to be paid. Phone lines have to be paid. Water, gas, sewage, electricity, trash, environmental disposal, property tax, inventory tax, income tax. Service manager, admin assistant, general manager, owner, service writer - all need to be paid, get vacation, sick leave, 401K, health insurance. Uniform rental service, mats and wipes service, shop supplies, shop chewing gum, wifi service for waiting room, lease on PCs and network routers, copier, fax, phone system, intenet access, landscape service, security system monitoring, security guard, workmans comp, general liability umbrella, fire, theft, and sixteen other kinds of insurance, and dental and vision for employees. The deler is being squeezed, not as many trucks being purchased (thanks Mr. President and elected brain trust); those that are financed at lower bank rates (dealer share is smaller), sales man and sale manager get some of it, and more people are selling their trade in themselves. So the dealer is trying to stay afloat and he can't afford to cut service rates.

Now the service tech gets a check, based on the flat rate manual or some other standard labor rate source times his percentage. Take out taxes, insurance, retirement, and there is enough left over for truck payments, gas, Snap On Tools Truck slush fund, Red Bull, coffee fund, and internet bill at home.

And instead of washing his wife's car, or mowing the lawn, or painting the house; he logs on and helps us mere mortals.

I say the pro techs deserve a special vote of thanks from all of us that they have helped.

 

Thank You for understanding my viewpoint Broken Rover

I can't answer for the dealer you visited for help. There is a good chance that they don't honestly know. There are not many Land Rover Techs that have stuck with the product since inception so there is a good chance the dealer you asked does not have a tech with much experience on P38.
That being said there is a very informative website for land rovers
RANGEROVERS.NET HOME there is an entire indexed archive of common problems and fixes for your vehicle...

To answer your door lock problem i would suspect you have faults with one or both front door latches. The microswitches get funky in them and they will ghost lock and unlock. I would start with replacing the one that makes the noise and if you still have a problem replace the other front one. I have never tried to fix one.. not worth the effort

The radio and nav, well it could a few things. i'll suggest 2. Make sure your key does not get stuck in the crank position while running.(I know the hvac will black out, don't remeber if radio and nav screen do) still worth checking out
Or your nav module may have locked up. I would try removing the nav cd module (r/r of vehicle)you can make a u shaped tool out of a coat hanger to release it, and unplug it, then see if the radio will come on.

I Don't really understand your cd player issue so I'm gonna say I don't know on this
one.

Cheers