Saleswoman in eating area by motorway (9)
I believe the answer is:
midinette
'saleswoman' is the definition.
(midinette is a kind of saleswoman)
'eating area by motorway' is the wordplay.
'eating area' becomes 'dinette' (I've seen this before).
'by' means one lot of letters go next to another.
'motorway' becomes 'MI' (resembles M1, English motorway).
'dinette' after 'mi' is 'MIDINETTE'.
'in' acts as a link.
(Other definitions for midinette that I've seen before include "Parisian shop-girl" , "French worker" , "Parisian salesgirl" , "Paris shop assistant" , "Foreign worker" .)