It suddenly struck me that, while everybody is running off looking at clips on YouTube, the British Pathe newsreel footage has been online for some time and I had never checked it out for tango.
The British Pathe site appears to be broken but the content is also accessible through the ITN Source page, simply do an advanced search and deselect all partners but British Pathe.
The first clip that attracted my interest was The New Tango from 1931, more for its filming techniques than anything. It shows a worms eye view of the steps as well as an amazing split shot showing worms eye view as well as a side on shot.
The second, of date unknown, was The French Tango. Yes, the French Tango which reinforces the old chestnut that the tango was introduced to the world via Marseilles and Paris.
The Argentine Tango, from 1928, including detail of the Valentino turn and the Solo.
And finally The Real Argentine Tango, which shows that performance pieces haven’t changed all that much 
Now I know where Cappusi and Flores get their material!!
Thank you, that was priceless!