I was late to this and spent a solid four hours yesterday afternoon attacking the beast. Some fiendish clueing from Mountain Ledges, which stretched my limits!
Just missing 21 across, which must have two clashes and totally stumped by it. Any hint appreciated.
May I request clarification of the preamble? I have assumed that the midway point will include the misprint and its correction, but haven't started that bit yet - going back to it this afternoon after my chores!!