Here are a selection of videos from the British Pathe youtube channel showing British tanks from the pre-WW2 era.
This first video shows an British Medium D tank being recovered from a river. David Fletcher’s book “Mechanised Force” mentions that in 1921 a Medium D tank sunk in the Themes (the medium D was intended to be able to float.)
From a WW1 war bond rally in the UK comes this footage of “Julian, the record breaking tank.”
From 1925 comes this “Thrilling Tank Display” from the Royal Tank Corps.
This video from an unknown location shows a WW1 British era tank being demonstrated to a crowd. We can only imagine how the crew felt after dropping over that edge in a vehicle with no suspension.
This footage of British medium and light tanks is labeled as being from 1935. Of particular interest is the footage at 1:20 which appears to show a couple Medium Mark III tanks, of which only three were constructed.
British Vickers Medium tanks shown being used for training in this video dated 1940. The Vickers Medium tanks Mark I and II had been retired from front line duty by 1940.
In this video from 1940, some British Cruiser Mark III tanks demonstrate their speed and agility.
This 1930 video is labeled “Salisbury Plain. First ‘All Tanks’ Manoeuvres. 250 tanks of all sizes take part in great ‘battle’ of Salisbury Plain.”