Some upset about parking in Derby town (5)
I believe the answer is:
epsom
'derby town' is the definition.
(I've seen this in another clue)
'some upset about parking' is the wordplay.
'upset' indicates an anagram.
'about' indicates putting letters inside.
'parking' becomes 'p' (abbreviation on road signs).
'some' anagrammed gives 'esom'.
'esom' placed around 'p' is 'EPSOM'.
'in' acts as a link.
(Other definitions for epsom that I've seen before include "Derby area" , "Derby and Oaks racecourse" , "Racetrack" , "Derby town" , "Surrey racing town" .)