Tank Medium , Mark A (E1949.328)
Though originally envisioned with a rotating turret, the production model had an armoured housing for three to four 303 Hotchkiss machine guns, which could be relocated between four gun ports. Approved in June 1917, roughly 200 vehicles were produced starting in October 1917.
While the heavy tanks were designed for direct attacks against enemy trenches the Tank Corps also wanted a lighter, faster tank to work with the cavalry over open country. Designed by Sir William Tritton and built by Fosters of Lincoln the Medium A, or Whippet, was the only such tank to see service with the Tank Corps, starting in 1918.
The Whippet was a difficult tank to drive; it had two engines, two clutches and two gearboxes but it was fast, by 1918 standards and very manoeuvrable in skilled hands. Even so experience soon showed that it was incapable of working with the cavalry and, in truth, should have been seen as an alternative. The Whippet was powered by a pair of Tylor four-cylinder engines, the same type that would be found in London buses of that period.
Only type of medium tank to see action in World War I.
Battlefront make a 15mm version.
I do think that this model would make for a great base for vehicles for an alternative Great War. It could be converted into a turreted tank, or a self propelled gun.