Finishes near central Ruislip (6)
I believe the answer is:
closes
'finishes' is the definition.
(close can mean to finish or end)
'near central ruislip' is the wordplay.
'near' becomes 'close' (synonyms).
'central' says to take the centre.
The middle of 'ruislip' is 's'.
'close'+'s'='CLOSES'
(Other definitions for closes that I've seen before include "comes to an end" , "Shuts" , "Wind up" .)