Seat sis mended breaks in Spain (7)
I believe the answer is:
siestas
'breaks in spain' is the definition.
(a siesta is a short sleep taken in Spain)
'seat sis mended' is the wordplay.
'mended' indicates anagramming the letters.
'seat'+'sis'='seatsis'
'seatsis' with letters rearranged gives 'SIESTAS'.
(Other definitions for siestas that I've seen before include "Assets I hide during naps" , "Afternoon naps" .)