1439 (XXI 1439) is allocated to Limavady. 1439 always would operate a school run from Loreto in Coleraine to Londonderry at around 15.30. Not 100% sure of any other workings 1439 does but expect to see it around the Limavady/Londonderry area.
Not sure about 176. Its not that often you see a Leopard operating a normal service in LD. But saying that I did get its sister 177 (VOI 177) one morning last year on the 09.15 Coleraine - Limavady but this is normally operated by 413 (FXI 413)