I'm afraid this gets the thumbs down from me. An hour to fill most of the grid and then several hours struggling to cold solve six of the thematic clues (all, of course, fully unchecked) and scrabbling around the Internet trying to find connections between known answers and unknown entries or known entries and unknown answers. In at least two cases the links were not the obvious ones, and I suspect one entry was a deliberate trap. There were a couple of straightforward examples, two others that could be linked without too much effort, but the rest were classic cases of GWIT, and distinctly unfair. Re Hagen's final comment, I'd had enough of it well before the end.
The Listener is supposed to be solvable without the Internet (I know of at least one puzzle that was rejected because of this house rule). I don't really see how someone without Google's search facilities could solve this unless their knowledge was encyclopaedic.