XII Corps Battle School near Folkestone?

Currently reading Richard Todd's first part of his autobiography - "Caught in the Act" - he writes about attending the "XII Corps Battle School" near Folkestone that most men nicknamed "Rat's Castle" or the "Slaughter House", I'm unable to find anything online relating to this, are there any books or Websites detailing anything about the Battle School?
Military Training in the British Army, 1940-1944: From Dunkirk to D-day has a little bit on the Battle Schools but perhaps not 25 pounds-worth.
It quotes Montgomery (one time XII Corps commander) as requiring all subalterns to attend the XII Corps School before taking command of troops. The two-week course was 'purely tactical' and is contrasted with IX Corps' school offering 'the familiar programme of lectures and TEWTs'.
Aha! Google Books provides a bit of a sneak preview here if you scroll about a bit.