If anyone else has this issue, my problem turned out to be a faulty speedo / instrument binnacle. This appears to feed the on-board computer and central display.

Hello all, I've recently picked up a 2002 L322 Vogue TD6 and as expected, it's not without its gremlins. I wonder if they could all be related? No trip display on either the central screen or the dash binnacle - just blank fields. The info screen is blank on the dash binnacle - it has the...