Listener 4570 Bright Spark By Shark
I found this extremely difficult. The clues were tougher (in my view) than we've had for a long time, not helped by the obstacles of clashes and well-disguised extra letters. Despite getting the theme quite quickly I ground to a halt in the NE corner, which took longer than the rest of the grid to complete.
Then there was the grid staring. I had a good idea of the sort of thing I was looking for, but it took me as long to find all the components as it did to fill the grid. That's a lot of time spent.
A brilliantly executed puzzle, but I found it so frustrating that for me this was one to admire rather than genuinely enjoy. Perhaps it wasn't as hard as it seemed and I'm just not a bright spark.