World War I
Early problems of stability on very hard or soft ground became apparent with the Mk VI, leading to the recoil system not functioning correctly. A Commission went to France to investigate, and a special level "Vickers platform" was adopted, to which the wheels and trail were secured for accurate shooting. A major change in the line of shooting required the platform to be relaid. Setting up and adjusting the platform was labour-intensive. The US manual describes it :-
"The platform consists of wooden beams which assemble to form a triangular platform. The spade must be removed and a special bracket fitted on the trail when using this platform. This bracket travels in a groove which gives a bearing for the bracket and also provides a means of traversing the piece 52° on the platform. The main objects in the use of the firing platform are: To provide a reliable support for the wheels and rear end of the trail, so as to prevent sinking or movement when firing on soft ground; to ensure the gun remaining on the target when firing; and to provide means for shifting the trail transversely through an angle of 52° (26° each side of center). By using the traversing gear on the carriage a total traverse of 30° on each side of the center is obtainable... The carriage wheels rest on steel plates on the wheel platform and are guided by curved-steel angles which prevent lateral movement of the gun off the target when in action. When the firing platform is used, the float plate, with spade attached, which is bolted to the underside of the trail, is removed and another float plate, having a thrust bracket attached, is bolted in its place".
At the end of World War I on the Western Front Canada had two 6-gun batteries, Australia 1, Britain 37. British 8-inch howitzer batteries serving in other theatres at the Armistice were : UK 1 (6 guns), Macedonia 1 (4 guns), and 2 guns in Palestine.
World War II
By the start of World War II some Mk 8 were still in use and were used in France in May to June 1940. After the Fall of France, remaining guns were used for training only. The advent of the BL 7.2-inch howitzer meant that remaining 8-inch barrels were relined to 7.2 inch. With no guns left, they were declared obsolete by July 1943.