That well-known short clip of the former Burns (and pre-Baldwin) guitar factory at Buckhurst Hill was recently indicated to have come from a Pathé newsreel. I have to say that at the time, I thought that was odd, since the clip is in colour and Pathé rarely used colour. Additionally, the film was clearly a feature and not "news".
My belief had been that the film had to have been extracted from a Rank/Gaumont "Look At Life" short (always made in colour and always feature-based rather than news-based). This was shaken somewhat by the attribution to Pathé, but the Rank/Gaumont "Look At Life" origin is now proven in a current BBC4 TV series compiled from LAL films from 1959 and later.
http://www.bbc.co.uk/iplayer/episode/b01nz93z/Britain_on_Film_Getting_Down_to_Business/
See the section at 28:12 onwards.
JN