British vehicle heading up round old city area towards the country? (6)
I believe the answer is:
suburb
'area towards the country?' is the definition.
(area further from the city centre)
'british vehicle heading up round old city' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'vehicle' becomes 'bus' (bus is a kind of vehicle).
'heading up' shows that the letters should be reversed in order (in a down clue, letters go up).
'round' means one lot of letters goes inside another.
'old city' becomes 'ur' (ancient city state).
'b'+'bus'='bbus'
'bbus' back-to-front is 'subb'.
'subb' enclosing 'ur' is 'SUBURB'.
(Other definitions for suburb that I've seen before include "Area on the periphery of a city" , "City's outer district" , "Area on the outskirts of a city" , "Outlying city district" , "Residential district on a city's outskirts" .)