Using IID Tool I noticed the other day and I noticed that the reading from the MAF sensor on one bank was showing 0 volts. I swapped the sensors over and the fault remained on the same side. I'm assuming I must have a wiring fault (L322 TDV8 '11) but I'm unsure where to look.

Any and all suggestions welcome. Thanks.

I could be wrong Mike but could that MAF sensor only start working when the secondary turbo fires up?

Ah, good point. I will have to drive it a bit harder and see what happens. I've had so many small wiring faults recently I just put 2 & 2 together and made 5.

The would be a fault showing on your IID code scan if a sensor was not functioning or out of a normal range. 2012 TDV8 Vogue (L322)

I first started looking in this area due to a message, such as:

"P0105-16 (6 Manifold absolute pressure/barometric Circuit - General electrical failure - circuit voltage was below threshold"

I suspect a one off issue then led me to spend too much time looking at the 0 volts output from the MAF sensor which was a distraction.

AFAIK there is just one MAP ( pressure sensor) which is on top of the plenum. There are MAF sensors on each intake airbox and an intake air temp sensor just before the throttle body. Only today on mine I noticed how hard the insulation was on the MAF sensor wires and how they were not covered so quite easy to imagine an internal breakage. Also worth pulling out the MAP sensor to check for soot fouling as this could cause a faulty reading. 2012 TDV8 Vogue (L322)

Yes, MAP is a single sensor in the plenum. Your error code hints to that but I'd first check it against the myriad of codes that are explained in the workshop manual (free in the Wiki). Just checked and it's in there under "Engine Control Module" in the "Diagnostic Trouble Codes" folder.
Easy to remove. Unclip wires, Torx25 and it pops out. I do it every oil change (6 months) and blast with brake cleaner. It's always a bit furry. Gone to a good home: 2011 4.4 TDV8 Vogue SE Buckingham Blue with Ivory and clear glass = "Rory"
2025MY Defender D350 90 in Silicon Silver on coils
1974 Series 3 Lightweight = "Millie"
Many, many other Landies over the years
My preferred specialist: www.glenrands.co.uk
--------------------------------------------------