There were 4 TV crews out on the eastern shore of the lake that morning, and 2 on a course boat. Starting from the south, on the eastern shoreline, you had Four Companies, filming in colour, about 1 km south of the southern end of the measured kilo. This was for the documentary, The Price of A Record
This is the film used subsequently used in Across the Lake, although the producers of that film flipped the footage to give the impression it was filmed from the western shoreline. All film of the crash should move from Right to Left for the first run, and Left to Right on the second.
Moving further up the lake, the BBC were filming from a course boat in the middle of the KM, close to the eastern shore. Just north of them were ITN and Redifusion filming from a position close to the northern marker on the shoreline. North of them, about 400m north of the northern end of the KM were Tyne Tees TV. All these crews filmed in black and white, with varying quality. Typically, the films from south and north of the km are better lit, and are better quality, albeit the boat is quite distant. The ITN, Redifusion and BBC are the classic B&W footage that is always shown.
That is the story of 5 of the film crews. The mystery is the Canadian Broadcasting Company footage, which was also shot in colour, from the launch used by the BBC. It, to the best of my knowledge, has never been seen. I have certainly never seen it, although like many, I believed the colour used in the drama doc Across The Lake must have been it, until I realised my error. (Don't let people tell you the colour film used in Across the Lake is this footage. It is not. That is the flipped Four Companies footage). Given the location CBC were stationed at, in the centre of the lake on a boat, that eliminates them as the source of this film. I can only assume that film must be spectacular, if it indeed does still exist.
As Mike said, there were a number of amateur film makers who captured the last two runs from the eastern shoreline, although given their distance from the subject, and the nature of their camera's, these films do not show any real detail of the boat and it's behaviour.
I hope that helps.
'When you go down into the arena, you know that sometimes, you're likely to get your nose punched. You do it with your eyes open. You take the risks' Donald Campbell, Bluebird and The Final Record Attempt. http://www.bluebirdk7.com