Mikey I understand but my car speedo registers 30mph when a satnav in the car shows 36mph. On travelling on motorways I set the cruise at 65mph to do 70-75mph, which as you say should be the other way round.
Is it possible to readjust the electronics of this?
The car has 255/55/19 tyres as it now has 19 inch wheels on it, but I don't think that should affect things as the rolling distance will remain the same.

Most speedos are set the other way, to read faster than you are actually travelling...

That's my problem - the speedo in this car is working in the opposite way to all other cars I have had. It is not a major issue as in a line of moving traffic I get used to travelling at 25-30 (actually30-35) or 35-40 (actually 40-50). My concern as is probably yours also is the average speed cameras on the A9 where you have to be careful not to drift above the limits.

Cameras on the A9 are a complete

I don't know if there is a setting for the pre-10MY L322 to adjust the speedo offset.
I know there is in the RRS/D3/D4 and newer L322

Thanks - speak to my local indy and ask him to have a look

Depends what diagnostic kit they have. I know Autologic couldn't adjust it, last time I used it...

What MY is your car?

It's a 2003 V8 4.4. Only been in my ownership 3 months to replace my old faithful Disco series 1.