There's a definite error on the online version. 22Ac & 20Dn.
The latter is a thematic answer (See 9Ac, 11Ac, 23Ac, 3Dn)
22Ac an Americanisme for toilet inside a 4 letter word for joints.
20Dn CORE reversed containing I on top of the first letter of 7 (ALBION)
Oh dear!
Sorry folks. I entered Guardian 23,394 (with comma), in the search and nothing came up, so I started a new thread. I should have known the eagle-eyed regulars were on it already. Thank you KAYAKAMINA.