[1] Horton took 76 on a windy second day and dropped a stroke behind the three leaders, Jimmy Martin, Sid Mouland and Lionel Platts who were tied on 143.
[2] Martin scored 68 on the final morning to lead by 3 strokes from Horton and Christy O'Connor Snr.
Dave Thomas has final round 67 to take the clubhouse lead on 285.
Martin missed a birdie putt from 10 feet and finished level with Thomas on 285.
Horton, however, drove into a bunker, missed a 5-foot putt and took a double-bogey 6 to finish one behind.