Thanks, JemimaB. I always find it interesting when people like or dislike a certain kind of clue - there's nearly always someone who'll disagree! My pet hate in the Spectator - often in Doc puzzles - is totally unfamiliar place names. I like to think I'm well-travelled, literally, but Doc really does test me at times.
You mentioned advertising and product placement - I remembered last night that a recent Doc puzzle had Cif, the cleaning product.