Asking for a friend - no, really.
Quick background: my elderly neighbour lost his driving licence a few weeks ago and since then I've been driving him to the shop every now and then. This is usually a week or two apart, so he sometimes starts the engine and idles it for a few minutes to charge the battery. He might have driven it around the parking area a bit but he doesn't even do that these days. Apart from when I drive him, the car is always parked inside the private parking area for the building.
A few weeks ago he had a visit from the police. Seems someone reported him driving! I assume one of the neighbours saw me driving him off and didn't bother to look how many people were in the car, but I digress. He told them he isn't driving on public roads, mentions me driving him around, and that he only charges the battery up every now and again. The police are satisfied and leave.
Fast forward to today. Once again, police are knocking on his door, only this time they're telling him he can't even sit in his car with his keys in the ignition, let alone the engine being on, as that would fall under "operating a vehicle without a licence". They threaten to take his keys away before he promises to not do it, and they leave.
Is this correct? Can he not even idle the car or drive it around a private residential parking lot, one with a sign warning "residents only", or would the fact that there is no gate or barrier to stop cars coming in deem it a public road?