I had to reverse engineer a lot of the Calendar clues, but enjoyed the hunt. I'm in awe of setters who can compose a puzzle like this. Both IQ and The Listener "pushing the boundaries" this week.
I too had to do a lot of back engineering, but it helped once understanding how the calendar clues were entered. It's funny how the IQ and Listener often share the same theme in different manners - but I don't mind being spoilt.