From central Spain and Madras, they obviously aren't all Spanish (7)
I believe the answer is:
armadas
'they obviously aren't all spanish' is the definition.
The definition suggests an adverb but the answer is not.
'from central spain and madras' is the wordplay.
'from' indicates an anagram (the anagram comes from the same letters).
'central' indicates the central letters.
'and' says to put letters next to each other.
The middle of 'spain' is 'a'.
'a' after 'madras' is 'madrasa'.
'madrasa' with letters rearranged gives 'ARMADAS'.
Can you help me to learn more?
(Other definitions for armadas that I've seen before include "Large fleet of ships" , "Fleets of warships" , "Large fleets, Spanish perhaps" , "task forces" .)