In November 1939 Lt Col Cleeve was tasked with forming a Super Heavy Railway Regiment and he searched Britain for railway mountings. He found three mountings rusting away in a shed at RAOC Depot Chilwell. They were Boche Buster, Scene Shifter and a third unfinished and not named later to become Gladiator, all empty of their barrels. later someone found Peacemaker and all were sent to be refurbished.
When Churchill looked the defences of the Dover area he ordered three 13.5inch barrels recently offered by the Navy - from the Duke class battleship reserves. The 13.5-inch barrels were designed to be close enough to the dimensions of the 14inch BL to be fitted to the same carriages. They were fitted to the 14-inch Mountings Gladiator, Scene-Shifter and Piecemaker. (Note the subtle change of name).
Here is Piecemaker outside Dover in March 1943