I declared a SORN on my 6 in July 2012 and excepting a 3000 mile, 2 week stint to Poland and back in March 2013, it has not been driven since. It will likely not see the road again until July 2015 at the earliest.
I have been regularly (each month or so, averaged) starting the engine to let it idle up to temperature and occasionally drive up to second gear & complete 5 point turns on the drive to give the gearbox, clutch, suspension and steering a slight workout.
My rationale is that it's better to get some movement and warmth into the engine etc. otherwise parts might seize up even more than they already will from being stood for ~3 years.
The negative of course is the repeated cold-start engine wear.
So, which is best?
Should I leave it alone completely and only fire it up in July '15?
How about cranking on the starter only, every month, to at least keep the engine moving but without the wear associated with a ~20 minute idle-from-cold scenario?
What have other people done in this situation?