I loved this puzzle. Sabre's clues are always tough but very fair, with no wasted words. Once I had an almost-full grid and the four 12s I made letter pairs and started building some strings of letters that looked plausible. An unusual word appeared and a quick hunt on Google led to the source material. It then took me a little more time to complete the phrase, fill the blanks, figure out the modification and find the cells to highlight. I made steady progress but was never stuck. This is pretty close to a perfect Listener in my view.