British Movietone have put a lot of old news clips on You Tube.
Here is a clip of the Chiswick Skid Pan but perhaps not what you might expect.
There is a clip about a series crash on Oxford Street. The scale of death is very surprising.
I don't remember hearing about that crash. The scale of death can probably be explained by the habits of the time, in that passengers queued for buses in an extremely orderly way, without gaps, so a bus crashing into a queue would almost certainly cause multiple casualties. I do remember as a young kid seeing an RT on the 13 that crashed into a shop in Regent Street, iirc as a result of driver illness. I can't honestly remember if anyone other than the driver died.