Just in case anyone needs them, I’ve found two specialists I’d recommend ;

1. Diamond Motors in Long Eaton for anything Renault, Nissan, Dacia, Alpine or Infiniti (where Nissan engined I.e. FX/QX70). He does a lot of the main dealer Renault Sports as they don’t trust their techs to get it right!

2. Brailsford Garage, Brailsford for older Land Rover products from Series 1 to P38, cheap and knowledgeable

Both are one man garages and have specialist knowledge.

For context got the Infiniti back today and bill was £975, this was for;

MoT
New rear discs and pads
Two tyre pressure monitors
Diff and transmission fluid change
Intermediate service

Clearly first diff and transmission fluid change in 114k miles.

Should add that included buying a specialist tool for the Infiniti