Hail not unusual in Scottish region (7)
I believe the answer is:
lothian
'scottish region' is the definition.
(I've seen this before)
'hail not unusual' is the wordplay.
'unusual' is an anagram indicator.
'hail'+'not'='hailnot'
'hailnot' is an anagram of 'LOTHIAN'.
'in' is the link.
(Other definitions for lothian that I've seen before include "Historic Scottish region" , "Edinburgh area" .)