It was traditional to marry in the wife's church, so possibly she was living in Larne at the time of marriage. Alternatively if the Ballynure church was unavailable for some reason (renovations), then that might require an alternative venue. For Church of Ireland it used to be a requirement that one of the couple live within the parish. Not sure whether the Presbyterian church, with its Presbytery system, had a similar obligation. Others will knwo, I am sure.