2000 GU II ZD30 Irregular starting problem

Hi all,
New to the forum and new to patrols. Hoping someone can help me with my problem.
I am having an irregularly recurrent problem with starting my patrol. I haven't owned it long so am unsure of its prior history.
The problem I’m having is occasionally when I go to start it behaves as if I have a flat battery, slow winding over, clicking etc, then eventually starts normally. I have also found after one of these incidents that the trip meter (not odometer) is reset to 0. I know it is not the battery as it is fairly new and is showing a full 12 volts with perfect charging/cranking etc when this isn’t happening.
My first thoughts were it was a problem with the NATS system as the remote is very fussy and sometimes only unlocks if I push lock first, so I decided to only lock and unlock with the key to bypass the remote, but the problem has reoccurred since.
So here I am asking the brains trust for help.

I think I would start by checking all earths for tightness and make sure there is no corrosion on any terminals. Check battery, and all connections. It sounds as though it could be a process of elimination as it could be a connections problem, a faulty ignition switch, faulty starter motor, NATS or even an engine issue. It will take a while to identify I recon as it is intermittent. As you say the battery is reading 12V, it might be worth reading the battery voltage from the + battery terminal and earthing at various points around the car to see if there is any volt drop through earth straps and such. Cant offer any suggestion as to why the trip would reset.

Thanks 4bye4,

I thought as much, was hoping someone would have a magic fix for me to avoid hours of tracing wiring problems. 🤣