Battlecruisers were the idea of Admiral Fisher. I read an interesting account, in an article about HMS Lion, from its Chief Gunner's Mate (the senior gunnery petty officer). He'd been posted aboard to replace the previous post holder, who seemingly had been sacked for something or other. He described what he found in and around the magazines (cordite charges mixed up and out of date, leaking bags, magazine and shell room doors open, at firing drills, etc.)and the steps he took to solve the problems.Her 'Q' main turret was hit and disabled at Jutland, but unlike Queen Mary and Indefatigable, which blew up after similar hits, she survived, seemingly mainly due to the tightening up of fire discipline which this CGM had instituted.