L405 starts but cut out when gear selector is moved.
Then car shows parking brake fault, followed by multiple faults hdc, htpc pcm and other acronyms I can't remember.
I've looked at DTC with sdd tool and there is no communication with several modules on the high speed canbus.

Any ideas would greatly appreciated.

Earth points in the front arches to start with

Thank you for that, makes sense aluminium and steel are not a good combination for earthing in the long term.

Due to work commitments I have had the car recovered to the local land rover specialist, I'll update the post with the prognosis. If I had the time I would have like to investigated further.

Update on the current situation.
Local land rover specialist has had an initial look at the car and confirmed multiple high canbus modules are not communicating with the diagnostics.
They say it is unlikely to be the the earth lead associated with the head light because both of the headlights are functioning.

More work to be done next week when their work load permits.

More tales of woe to follow I'm sure.