Around middle of autumn, at last we reviewed a kind of legislation (7,3)
I believe the answer is:
statute law
'a kind of legislation' is the definition.
'around middle of autumn at last we reviewed' is the wordplay.
'around' is an insertion indicator.
'middle of' indicates the central letters.
'reviewed' indicates an anagram (To look at again and re view).
The central letters of 'autumn' are 'tu'.
'at'+'last'+'we'='atlastwe'
'atlastwe' is an anagram of 'statelaw'.
'tu' going into 'statelaw' is 'STATUTE-LAW'.
(Other definitions for statute law that I've seen before include "Body of rules" , "output of 11 [LAWMAKER] ?" , "Legislation enacted by Parliament" .)