I'm having a hard time trying to convince myself this was the result of an autorotation. As someone else said, a 7-8ft drop from a roof you would expect to survive.
I'm just thinking the plotted course and height as shown re PB would indicate where this started from, and might shed more light on a cause.
I notice the police are now appealing for all video and audio recordings the public took of the scene before and after the incident.
BBC News - Glasgow helicopter crash: Police appeal for Clutha tragedy video