What did you say in loo about port? (2,5)
I believe the answer is:
le havre
'port?' is the definition.
(I've seen this before)
'what did you say in loo about' is the wordplay.
'what did you say' becomes 'eh' ('eh' is used to ask someone to repeat something).
'in' means one lot of letters goes inside another.
'loo' becomes 'lav' (lavatory).
'about' becomes 're' ('re' means regarding or about).
'eh' going within 'lav' is 'lehav'.
'lehav'+'re'='LE HAVRE'
(Other definitions for le havre that I've seen before include "Port city of northern France" , "Port in Normandy" , "Northern French port" , "French Channel port" .)