This is a Desoutter Mk 1, according to the CAA's database of registrations; I'd never seen one before when I happened upon it at Old Warden, where it's kept by the Shuttleworth Trust. I think that it's rather an attractive machine and there are three engineers giving it an engine run.
I'm rather pleased with the prop blur that I've achieved . . .
The extra shot is one of the engineers attempting to start it by swinging the propellor. He didn't succeed, but someone who appeared to have the knack waltzed out of the hangar and gave it a good swing to start the motor.