Mother takes girl back to a Spanish resort (6)
I believe the answer is:
Here is my best explanation:
'spanish resort' is the definition.
(I've seen this before)
'mother takes girl back to a' is the wordplay.
'mother' becomes 'ma' (ma is a kind of mother).
'takes' says to put letters next to each other.
'girl' becomes 'gal' ('gal' can be a synonym of 'girl'**).
'back' is a reversal indicator.
'to' is a charade indicator (letters next to each other).
'gal' written backwards gives 'lag'.
(Other definitions for malaga that I've seen before include "Spanish port and resort town", "Costa del Sol resort", "City of Andalusia", "Sweet wine; Spanish port", "Southern Spanish city and resort", "Andalusian city", "Resort in Andalusia", "Place", "Army rank; not shared" and "Andalusian port; wine".)