A seat in the south, also at Leatherhead (5)
I believe the answer is:
stool
'a seat' is the definition.
(stool is a kind of seat)
'south also at leatherhead' is the wordplay.
'south' becomes 's' ('S' can be a synonym of 'south').
'also' becomes 'too' ('too' can be a synonym of 'also').
'at' is a charade indicator (letters next to each other).
'leatherhead' becomes 'l' (head letter of 'leather').
's'+'too'+'l'='STOOL'
'in the' is the link.
(Other definitions for stool that I've seen before include "place butt on one?" , "Simple seat" , "Small seat" , "Motion" , "Seat without a back" .)