Enormous shop there - my park is ruined (11)
I believe the answer is:
hypermarket
'enormous shop' is the definition.
(I've seen this before)
'there my park is ruined' is the wordplay.
'is ruined' indicates anagramming the letters.
'there'+'my'+'park'='theremypark'
'theremypark' is an anagram of 'HYPERMARKET'.
(Other definitions for hypermarket that I've seen before include "Very large self-service store" , "Big out-of-town shop" , "Vast shop" , "Super-superstore" , "Enormous shop" .)