Heriot’s never looked back after grabbing the perfect start when Simpson’s speed left the Gala defence stretched and the full-back scored in the corner after five minutes.
Gala were forced to bring on Rob Louw for the injured Harry Borthwick and Ruaridh Mitchell was replaced by Stewart Mustard for Heriot’s.
Gala continued with the pressure before Heriot’s regained composure and a Graham Speirs clearance kept their line intact.
Gala ended the half strongly with a Craig Robertson break as Heriot’s turned round 5-0 ahead.
On the restart, Heriot’s passed up a second kick at goal as the visitors pressed for a try, which Michael Liness scored and Andrew Simmers converted.
Heriot’s were now in charge, Gavin Parker scoring a third try which Simmers converted. The Goldenacre side rounded things off with Simpson’s second try and a bonus point.