I have an 07 TDV8, a couple of weeks ago it was flat when trying to start it so I jumped it and it was fine. I tested the voltage across the battery with a meter and it was 11.95, after a few minutes this had gone up to 13.95.

Does the alternator not kick in straight away?

Anyway, I left the car for 5 days and it started fine so I presumed I had just left an interior light on or something. The car has been fine since except for today when it again would not start. Once started it gives me lots of strange error warnings such as special programs not available and suspension fault, I presume these are voltage related.

Once it has been driven for a while the car is back to normal. Does this point to the battery? I just left the car and the battery is showing 12.65 volts, I will test again in the morning and see if it has dropped.

Change your battery for a new one. I had the same issues, loss of special programs etc, then it died. Was still showing 11-12 volts but wouldn’t start. New battery has cured all. Previously owned 1999 Disco 2 TD5
Disco 3 HSE TDV6 2007
Gone 2007 TDV8 RRS1 in Buckingham Blue.

How do know if the knocking at the front has been sorted?

You can hear the knocking at the rear better