Message sent back about American station in London (6)
I believe the answer is:
euston
'station in london' is the definition.
'euston' can be an answer for 'station' (London train station). I'm unsure of the 'in london' bit.
'message sent back about american' is the wordplay.
'message' becomes 'note' (note is a kind of message).
'sent back' says the letters should be written in reverse.
'about' indicates putting letters inside.
'american' becomes 'us' (abbreviation for United States).
'note' backwards is 'eton'.
'eton' enclosing 'us' is 'EUSTON'.
Can you help me to learn more?
(Other definitions for euston that I've seen before include "North London terminus" , "trains here in London?" , "north London area" , "Brown seaweed" , "London rail terminus" .)