Garaging usually works out cheaper for me, but I'm not THAT suprised that garaging attracts a premium over road (although how it does over a driveway I'll never know). Like a few have said, if someone gets into your house and you have a garage, it's game over.They WILL take the car, or at least have time to get into your car without anyone being the wiser. Then you probably have a fair amount of claims of car damage resulting from house damage, eg fires..
It's wierd though. My insurance worked out to be about 350 quid cheapest. Moving reduced it down to about 280. But the same move made my bike insurance go up by 30 quid even though the garage is more secure and it's a less populated area - AND my bike was stolen at the old address