The Stirling-born wing/full back has signed for the Warriors on a two year deal from Bristol.
"I'm pleased for Sean that he's come to a decision. We didn't really want him to leave as he's done well for us despite having a wretched season last year with the hamstring problem," said coach, Richard Hill.
"However, we've now got him back on the track to fitness and he's got a tremendous opportunity to play in the Celtic League. I actually think he's made a wise choice."
"We wish him all the best. He's been tremendous for us, always given us 100% on and off the field and been a brilliant lad to coach and have in the team. I really do hope he makes a go of it up there."