Cryptic crossword No 514

As the theme may not be immediately obvious to anyone other than the birthday boy, and to avoid frustration, an explanation of the thematic solutions is given in reply to this post. NB: Spoilers, so only read once the puzzle is solved.

Goodness, Catnip. Intrigued by this, I checked and I see you have only appeared on MyC once and that was over a year ago with your first puzzle. If this is your second, I'm not surprised it's taken a year. This had a distinctly professional feel to it as I was going through. Surfaces are splendid and little to quibble about. 14a, 22a, 26a, 27a, 5d, 7d, 8d, 17d and 24d. Maybe the odd DBE indicator needed but I enjoyed this enough it's churlish to be critical. Thanks. PM