I found this to be a very enjoyable puzzle. Pairing the additional words baffled me for a while until a massive PDM led me to the thematic source. Even so, I wouldn't have got them all without wiki and google. I have just shaded the blanks, but I am not 100% sure that that is what is intended.
Thanks Will. I googled the thematic source and the message from the re-arranged initial clue letters and immediately saw what I needed to do. Doubly a very clever ending.
Filled the grid first, as there are not that many options giving real words - rotational/diagonal symmetry helped.
Just got the twelfth pairing - which agrees with my grid.
Now back to last week’s puzzle !
Just finished. A really enjoyable puzzle. Got a bit bogged down after filling in a few clues, but then twigged the theme after identifying one (the first) of the extra words. And then right at the end I spotted something else that had been staring me in the face the whole time and I cursed and laughed in quick succession
mafu, I have no doubt that what had been staring you in the face also what led me to my PDM - I didn't laugh but I did curse. I thought that it was an ingenious Easter egg.