I know I’m late but thought I’d add:
My FOI was 25A, which gave me 25D as my first SI. I was them convinced that the 12 were the Chinese ‘zodiac’, another group of 12 not mentioned, and wasted ages trying to find them before I realised I was wasting my time. Ironically I (like others) struggled with NE corner and 6d, one of only two other SIs from the Chinese list, ended up my LOI!
Altogether good fun, thanks to Boatman and thanks as ever for all the chat and hints here.
I get the printed paper but, again like others, I do not see the SIs on my iPad, I’ll ask The Guardian why not and let you know if I get a response