Bore wear, engine wear.

[Chris KC]

I would suggest don't start it unless you plan to drive it somewhere.

That's what I thought at first. But starting it for one minute means one minute of cold running, only. Starting and driving for half an hour means a full ten minutes of cold running plus 20 minutes of hot running. That seems to be far more likely to cause serious wear.

I meant leave it alone unless you plan to use the car. Mine regularly stands idle for a while with no ill effects. Wear happens every time you start the engine but that's inevitable. Plenty of owners use their A7's throughout the winter months without any issue.

When you do drive, wait till the engine is properly warm before attempting any heroics. And don't forget that water temperature and oil temperature are completely unrelated (especially if you use straight engine oil). 

There's a guy up the road who keeps a very expensive car in a lock-up next to my house, he's been through a string of different marques. Never drives them anywhere as far as I can tell, but diligently comes down every week or two, starts the engine and revs it in his garage for 5 minutes (presumably on full choke). Some day I will explain to him not only how irritating he is, but how much damage he is doing to his car; but he doesn't strike me as the listening type.