Just out of interest, having already finished the crossword, I took that PDF and asked ChatGPT to turn it into a puz file. It did pretty well. It got the format wrong first of all, but corrected it with some prompting and I was able to load it into squares dot io.
Probably easier than wrestling with the observer website trying to get the puzzle to display.
Thanks plutocrat but my antivirus is taking great exception to that link 😄 probably the usual nanny-state overreaction from the software, but I didn't continue. On another tack, is it me or are there a lot of anagrams in today's puzzle?