Ah.....got it. THOSE missing words! Now that does make it easier. So used to confusing preambles I tried to read too much into this. Nearly there with the grid but starting to worry about the mysterious ambiguity.
Finished. Now just puzzling over the significance of the milestone. I have a feeling I might be missing the obvious, but I blame the Easter sparkly and my mother in law bending my ear.
Yes, rrrobbo, a bit of self-indulgence by the setters really, without too much thought about including the solvers in a good solve. A far cry from "...one of the main pinnacles of the crossword world..."