I've just finished this and I expect other people have puzzled over one or two clues.
13 Across is "Turn left at top of steps
for the MBA seminar". Answer is
"business class" but I can't tie the
first half of the clue in.
Secondly, 5 Down is "Half the heart's
movement that's subconscious". Answer
is "tic" but I don't fully see that
one either!