Home Counties setting for extremely tacky eyesore (4)
I believe the answer is:
stye
'eyesore' is the definition.
(I've seen this before)
'home counties setting for extremely tacky' is the wordplay.
'home counties' becomes 'se'.
'setting for' indicates putting letters inside.
'extremely' suggests removing the centre.
'tacky' with its centre taken out is 'ty'.
'se' enclosing 'ty' is 'STYE'.
(Other definitions for stye that I've seen before include "makes viewer sore" , "Red eye" , "Eyelid infection" , "Eye blemish" , "Tamworth residence" .)