I thoroughly enjoyed this one. As a composer, I don't care how long it takes me to solve a puzzle, nor whether I find it easy or difficult. It's the originality of the idea and the elegance with which it is realised that interest me. I have seen this idea used before, but in a different format, in which the answer itself directed the method of entry of the relevant light (for example: answer HALF-BACK; light FLAH). Here instead we had 10 pairs of thematic words in a symmetrical 13 x 13, with entertaining clues. It could have been improved by making all the lights proper words, and for perfection the pairs would have been symmetrically placed. But is it possible to contruct such a grid?
For those who are curious about the Ronnie Scott connection, the relevant clue appeared in Spectator 2064 (19 May), "Not in Colour" by Doc: "This wind nonet's initially tried out at Ronnie Scott's". In contrast to Nudd's clue, Doc's has nothing to do with jazz and is in fact a comp anag.