Perform check, covering county where Homer settled? (7)
I believe the answer is:
dovecot
'where homer settled?' is the definition.
(homer can mean homing pigeon)
'perform check covering county' is the wordplay.
'perform' becomes 'do' ('do' can be a synonym of 'perform').
'check' becomes 'vet' (I've seen this before**).
'covering' means one lot of letters goes inside another.
'county' becomes 'co'.
'vet' placed around 'co' is 'vecot'.
'do'+'vecot'='DOVECOT'
(Other definitions for dovecot that I've seen before include "bird sanctuary" , "home for peacemongers?" , "Pigeon shelter" , "accommodation for fliers" , "Pigeon roost" .)