While wasting time on Reddit I found this short film. It shows 3 (I think) Mark V tanks, and 2 Medium B tanks. It was captioned as "WWI Vintage Mark V Tanks in Soviet Service captured during the Initial stages of Barbarossa"
Latvia acquired 3 Mark V and 2 Medium B tanks after the British Russian Expeditionary force left in 1919. The Latvian Army also had 3 or 4 Daimler
Marienwagen half tracks in service between the wars. I'll have to step through the video but I think there might be one or two of these in the vehicle collection
as well.
Is there any indication of who shot the video and when?
No. I found the video quite by accident on Reddit, in the horribly named sub-reddit "tankporn". The only information I could see was the title. If you're more adventurous than me, you might be able to make further enquiry on Reddit, but, personally, I always feel rather dirty after spending any time there.
The Osprey books on Armored Units of the Russian Civil War have Estonia getting in 1919 4 Mark Vs from the Whites. They were captured by the Soviets in 1940 and were used by the Soviets in the defense of Tallin in August 1941.