Is there a difference between the genuine Land Rover Test Book used by main dealers and the Commercial Diagnosis computer used by garages.

 

Yes, about $25,000 worth.
Why do you ask, what are you trying to diagnos? After market lap top type scanner will do most of what is needed on your truck.

 

In a thread about 2 weeks ago, I raised a problem with the central locking and a flashing 'crossed D' on the gear selector dash LCD. I had the car diagnosed by a local garage which used a kit to determine any faults that may have been stored - but it picked nothing.

I don't intent to go to the main dealer, but was wondering if the kit they use is different to local garages.

 

You need to find a shop with a lap top type scanner, like an Auto Logic scanner, there are many out there that can access Rover codes.