Greece advanced Spanish nothing for their city (7)
I believe the answer is:
granada
'city' is the definition.
(I've seen this before)
'greece advanced spanish nothing' is the wordplay.
'greece' becomes 'gr' (abbreviation).
'advanced' becomes 'a'.
'spanish nothing' becomes 'nada' ('nothing' in Spanish).
'gr'+'a'+'nada'='GRANADA'
'for their' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
(Other definitions for granada that I've seen before include "City in southern Spain, site of the Alhambra" , "car in > Spanish city" , "sunny city" , "City of Andalusia" , "Andalusian city" .)