I can't remember where I eventually found the relevant post but thank you!! Had the issue of multiple warning llights, gearbox fault, engine management warning HDC, DSC, ABS etc. ok for a couple of days then Bing Bing....
Found the faulty corroded earth stud on drivers side, drilled and tapped a new thread and cleaned all contact areas..... sorted!! many pennies saved thanks to wise word on this forum!!!
 Gone
*1997 Discovery 200tdi
*1989 Range Rover Classic 3.9
*Discovery TD5 ES
*Discovery TD5 ES facelift
*Discovery 3 TDV6 7 seat auto
*Range Rover vogue SE 2006

Agree, you can’t beat an active community forum, as a decades long Range Rover owner there’s always more to learn. Maybe you should include more details with photos etc for this one, if you get the time. You sound pretty handy with a spanner/drill! L405 P400e Autobiography (MY2020)... Silicon Silver / Espresso