Well if this was my blue car parked on a hilly road like this, I wouldn't be very happy at all. You could not get a wafer thin piece of paper between the grey and blue car and there wasn't much more room at the front.
I think it would be easier to get it out with a forklift truck than to make 40 or 50 moves to wiggle out of this tight squeeze. There are some very thoughtless people out there, unless the owner of the blue car also owns the grey one and is holding it up the hill.
Astra if I am not mistaken they are prone to roll !? One ended up the other week in the front of a house in Suffolk and our fleet had the same experience also