A good puzzle overall, I felt, for which many thanks to Tangram.
Some easy clues; some hard. Like Z, I made a couple of mistakes with my solutions including, I suspect, the same mistake with 1d. So I'll be checking everything thoroughly this weekend.
I think Tangram would have had problems asking us to prove we had answered his question. Highlighting, for instance, would have been ambiguous with two 3-letter words in the grid providing a viable alternative. He would have had to tell us how many letters to highlight which could have helped us to solve the puzzle. Similar difficulties occur with writing something below the grid.