Where it's jolly good to enter, perhaps, for a race (7)
I believe the answer is:
aintree
'where it's jolly good' is the definition.
I know nothing about this answer so I can't tell whether this works.
'enter perhaps for a race' is the wordplay.
'perhaps' indicates an anagram.
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'race' becomes 'i' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'enter' is an anagram of 'ntree'.
'a'+'i'='ai'
'ntree' after 'ai' is 'AINTREE'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for aintree that I've seen before include "place for horse racing" , "6 National course" , "Venue of the Grand National race" , "Merseyside racecourse" , "Liverpool's racecourse" .)