Many thanks, listenup, for parsing of 13ac, which I also couldn’t get. But is the definition actually “rat out of”? Chambers gives “rat out” - “to betray the interests of” - but not, as far as I can see, “rat out of”. But then the “of” doesn’t seem to do anything in the clue, even as a joining word.
Also, Chambers gives “bar” as an archaic definition of “estop”, but the legal meaning is “to hinder or preclude”, which is current.
I am now off to undertake a thematically-related activity.