Here are some links which have proved useful in the research
Background on the formation of siege batteries http://1914-1918.invisionzone.com/forums/index.php?app=blog&module=display§ion=blog&blogid=436&showentry=1300
Link to the Forum site home page http://1914-1918.invisionzone.com/forums/index.php?act=idx
Information on the 6" Howitzer http://www.landships.freeservers.com/gander_onthe_6inch_howitzer.htm
Link to the Forum site home page http://1914-1918.invisionzone.com/forums/index.php?act=idx
Information on the 6" Howitzer http://www.landships.freeservers.com/gander_onthe_6inch_howitzer.htm