This is the Vickers Medium Mark II* at the Bovington Tank Museum.
It was the main British tank from 1923 until 1935.
Introduced in 1923 the Vickers Mediums were the first British tanks to see service fitted with a sprung suspension and a rotating turret. Designed to fight on the move, their high speed of 30 mph restored mobility to the battlefield. The hull was riveted. The engine, an air cooled Armstrong Siddeley, was mounted in the front of the tank, alongside the driver. Originally described as a light tank, the advent of even smaller tanks weighing about five tons, resulted in the Vickers’ design being reclassified as a medium tank.
The Medium Mark II was completely obsolete by the beginning of World War II. The survivors were used for training during the first few years of the War. Some were issued to combat forces to make up their strength after the loss of most British first line tanks during the retreat from France in 1940. Others were sent to Egypt as training vehicles and were pressed into service with the Western Desert Force. They were buried as fixed defences at Mersa Matruh and Tobruk.
Vickers sold 15 Medium Tanks to the Soviet Union in 1930, they were used for training. Rather surprisingly, the Finns captured half a dozen of these relics from the Russians in the autumn of 1941. At least one other went to Australia, while a single example of a developed version, the Mark C, was sold to Japan. This vehicle formed the basis of the Japanese Type 89 tank design. A single example of the final version, the Medium Mark D, was sold to Eire where it remained in service until 1940.
These would be the mainstay tanks of any A Very British Civil War scenarios. Difficult to get hold of relevant models though, but you can find 3D printed versions online.