I won't be using the car for a while so I have taken the car off the road but it will remain on the drive. I have done the SORN thing and cancelled my insurance. After a moments reflection I considered the need to insure my car should it be damaged or stolen while on the drive. My home insurance won't cover it and the form for getting a quote via Moneysupermarket seems to assume (understandably) that the vehicle will be driven. Does this mean that no such insurance exists or I need to look elsewhere?

You need to look for a, "laid up policy" that still covers the car against the risks you require, but excludes events arising from vehicular use on the public highway.

Stick the words, "laid up car insurance" into Google for more details.