I experienced the same as most others, I imagine. I was on the point of giving up after hours of solving, when the first penny dropped, enabling me to see how to correctly parse answers that I already had. The second penny dropped a little later, allowing me to trot to the finish. The wordplay to one answer still eludes me. I had the wrong answer until the very end.
I don't see the need for 'Scottish' in 10d. It's not wrong, but it's not necessary, and just adds one more fiddly element to the chaos.
Most Listener puzzles take a lot longer for the setter to compile than for the solver to solve. In this case the setting time might well have been less than the solving time. The grid is a stock one from Sympathy, the crossword construction program, and autofill would have filled it in seconds. Maybe a few minutes more to get in some preferred entries. The clue-writing would have taken a few hours, of course, and the clues do have some nice surface readings.