Not The Saturday Prize Puzzle

NTSPP - 403 by Elgar
“Theme and Variations”

This puzzle was distributed at the S&B meeting in York on Saturday 29 October.

An actress, on fire at The Fringe, should assist solvers in identifying a two-word phrase (the THEME, to be highlighted in the completed grid) that connects three groups of answers, each with four members (the twelve VARIATIONS).