At Chelsea, say, going north in a bus (4)
I believe the answer is:
buns
'at chelsea say going' is the definition.
I can't judge whether this definition defines the answer.
'north in a bus' is the wordplay.
'north' becomes 'N' (synonyms).
'in' is an insertion indicator.
'n' inserted within 'bus' is 'BUNS'.
Can you help me to learn more?
(Other definitions for buns that I've seen before include "Food items" , "Small rolls" , "Cakes" .)