Gavin is in his third spell at the club. Originally signed for Harps in 1998 he spent some time in the youth and reserve sides during that season. Later went to Omagh Town for a couple of seasons, where he established himself as one of the top keepers in the Irish League, but came back on loan in 2003 where he kept a clean sheet in each of the six league games which he played. Harps finally captured his permanent signature prior to the start of 2004 season before loaning Cullen out to Newry City towards the end of last season. Was first choice keeper in the 2005 season.