Gang abandoning base in Cheshire town (4)
I believe the answer is:
crew
'gang' is the definition.
(I know that gang can be written as crew)
'abandoning base in cheshire town' is the wordplay.
'abandoning base in' means to remove the last letter (in a down clue, base can mean the bottom letter).
'cheshire town' becomes 'crewe' (I've seen this before).
'crewe' with its final letter taken off is 'CREW'.
(Other definitions for crew that I've seen before include "Rowing team" , "Ship/plane operators" , "Gave wake-up call" , "Team who man a ship" , "Sailors -- boasted" .)