The former Scottish Strokeplay champion from Clydebank posted an opening three-under 69 to finish in a share of fourth spot, four shots behind early pacesetter Dale Marmion.
One-over at the turn, Henry, 23, battled back on the inward half and reeled off four birdies to move into the title hunt.
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Hide AdMartin Lawrence is the next-best Scot on 71 with former Scottish PGA champion Jason McCreadie a stroke further back on 72.
Zack Saltman and Barry Hune both opened with 73s but former EuroPro Tour winner Elliot Saltman slipped to a 76.