All wrong, when around inside opera house (2,5)
I believe the answer is:
la scala
'opera house' is the definition.
(I've seen this before)
'all wrong when around inside' is the wordplay.
'wrong' is an anagram indicator.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'around' becomes 'ca' (circa).
'inside' is an insertion indicator.
'as'+'ca'='asca'
'all' is an anagram of 'lla'.
'lla' going around 'asca' is 'LA SCALA'.
(Other definitions for la scala that I've seen before include "A Callas may find way to Milan's famous opera house" , "A Callas seen in famous Milan opera house" , "Milanese opera house" , "place to sing" , "noted venue?" .)