 Complete the following phrase:  70th Siege Battery was formed at Dover under War Office Instruction No 144 of 9 October 1915 from one company probably 14th Company of the Forth RGA, which provided half the personnel. It went out to the Western Front on 26 March 1916 armed with four 8-inch howitzers and joined the Northern Heavy Group 40th Heavy Artillery Group or HAG in X Corps. This Corps was part of Fourth Army preparing for that summers Big Push the 