[RinskyJinsky]

Following on from my previous post, we finally got our car to an authorised Volvo service centre where they were unable to diagnose the issue so it went to a Volvo dealership. There they did some kind of connection between the car and some service centre in Sweden to allow them to remote connect to the car and do some advanced diagnostics.

Turned out to be one of the control modules - specifically the one relating the immobiliser that had failed. This had meant the car wouldn't receive the command to release the immobiliser when the ignition was started, even though he key was recognised. Evidently the handbrake is also part of the immobilisation system on the XC90 as the handbrake couldn't be released and the only way they could tow the car was on skids for the back wheels.

Once the control module had been replaced the car has been running fine ever since.

We had one of those after-market warranties with the car so we didn't have to pay the invoice which came to about £1,500 for the repairs and I didn't get a copy, but I will contact the garage and see if I can get a copy to post the exact description of the issue on here in case it helps anyone else.