Some concern at a lough in the old province overseas (5)
I believe the answer is:
natal
'the old province overseas' is the definition.
I can't judge whether this definition defines the answer.
'some concern at a lough' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'NATAL' is hidden within 'concern at a lough'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for natal that I've seen before include "Relating to the time of one's birth" , "dealing with delivery" , "Of or from one's birth - in S African province" , "Pertaining to birth" , "Former African place" .)