Hi Woodlouse, once I found the answer I did remember that I'd once known it...if that makes any sense. I thought that there was a slight weakness in the endgame, in that whatever letters the solver already had for 1A, 1D & 4D, and the equivalent opposite entries, these were very useful for finding the replacement words for thematic clues 5, 6, & 7 and 2, 3, & 4 respectively. There was no such assistance for thematic clue 1.