Composer, about five, takes ecstasy in port (2,5)
I believe the answer is:
'port' is the definition.
(Le Havre is a French port)
'composer about five takes ecstasy' is the wordplay.
'composer' becomes 'lehar' (Austro-Hungarian composer Franz Lehar).
'about' indicates putting letters inside.
'five' becomes 'V' (Roman numeral).
'takes' says to put letters next to each other.
'ecstasy' becomes 'E' (informal term for the drug).
'lehar' enclosing 'v' is 'lehavr'.
'in' is the link.
(Other definitions for le havre that I've seen before include "French Channel port" , "Port in Normandy" , "Port city of northern France" , "Northern French port" .)