Major Electronic Failure

My RR P38 4.6 HSE 1995 today displayed the message "Major Electronic Failure" with all indicators on the panel blinking like a christmas tree. My official Land Rover mechanic, who made this happen, says he has never seen this message and does not have a clue what it stands for and what causes it. Myself I can not find this message in any of my RR manuals. After reset of the system everything worked fine, until next time.....
The car just had a powerful new battery installed, and was being started in temperatures well below freezing point.
Has anyone seen this message and if so can tell what caused it?
Thank you in advance.
Henrik

I say make your mechanic pay for this repair............