Not for the first time, I set a cryptic aside yesterday after maybe an hour's fruitless staring at four last clues. I picked it up again this afternoon and answered all four in under a minute.
Does this ever happen to anyone else and if so, any thoughts on why it does?
I think Pixie's just said what I was going to... if you become fixated on one, wrong, idea for something then it can act as a block until you stop thinking about it consciously. Then on a second look a new idea can occur to you, and this might be the right one or not but the break certainly helps.