Disco 2 Wont Start

2004 Facelift (Manual)
Engine wont turn over,everything seems dead
Put key in ignition and wont start not cranking, all that happens is i get 6 like audible alarm pings
My key fob has not worked for years i just open manually, noticed this time all the other doors don't unlock.
Alarm LED on dash not lit or flashing
Thought it might of been battery so charged it up and still the same.

Red LED flashing on Navigation System goes of when turn key

Also flashing symbol in the digital mileage display looks like a B

Is there any fuses for ECU,I have nanocam so if there is anything that I could check (limited use on this)T
Things that don't work
Windows
Indicators
Seats
Sun Roofs
Central Locking

Things that work
Horn
Blower
Wipers
Lights
lighter

Any help appreciated

Taza

Guys Just an update on the fault, before I started going down removing the BCU unit I thought I would take a chance and put a Electric Heater inside the car,

1. Disconnected Battery
2. Unplugged all the connections on BCU
3. Put electric heater in the footwell pointing up at the unit
4. Left for couple of hours
5. Fitted all plugs back
6. Connected Battery Back Up
7. Bingo it started

Sometimes the simple things work!
Good for you!

Guys the dreaded fault is back, and its not been raining.
Put the heater on it again and it started ok,went out this morning and it wont start again.
Is it the BCU if so if I buy a new one what do I have to do to set it all up, I have the Nanocam diagnostic tool.
If I get it going again what information should I write down from the Nanocam to reset the new BCU

Any help appreciated

Taza