I've a full grid and have made the necessary change to get the precursor but as always, despite endless grid-staring, I can't see what needs highlighting. A nudge/violent thrust in the right direction would be much appreciated.
AP consider the title of the puzzle and the language used to identify the product. Also what is nowadays - in a commercial setting anyway - a pretty miserly helping thereof.
Thank you for that Jack. I can see what might be considered a miserly measure and will go back to find (hopefully) the one associated with the puzzle's title. As is my wont I've also been misreading the preamble and looking for 23 cells to highlight in addition to and not including the changed entries.