Left charge for allotment (7)
I believe the answer is:
portion
'for allotment' is the definition.
(portion is a kind of allotment)
'left charge' is the wordplay.
'left' becomes 'port' (left side of a ship - opposite of starboard).
'charge' becomes 'ion' (an ion is a charged particle).
'port'+'ion'='PORTION'
(Other definitions for portion that I've seen before include "Part - share" , "Part of a whole" , "allotment" , "Segment" , "Piece of a whole" .)