Girl has an untidy place that's idyllic (7-2)
I believe the answer is:
shangri-la
'that's idyllic' is the definition.
(I know that Shangri-La is idyllic)
'girl has an untidy' is the wordplay.
'untidy' is an anagram indicator.
'girl'+'has'+'an'='girlhasan'
'girlhasan' anagrammed gives 'SHANGRI-LA'.
'place' is the link.
(Other definitions for shangri-la that I've seen before include "Earthly paradise (from Hilton's "Lost Horizon")" , "Fictional paradise on earth" , "Fictional Tibetan paradise from novel 'Lost Horizon'" , "Imaginary earthly paradise" , "Milk" .)