S76C++ can easily be flown from either seat. We had new 250hr co-pilots who would fly from either seat depending on who they were flying with. Captains decision. (note captain, not line trainer or TRI etc) We didnt need to be line trainers to fly with the new guys.
I was nothing more than a Line Pilot and low time at that.
Anyway, with nearly every new co-pilot I flew with, I always got them to do a full flight back to base with me acting incapacitated and just watching how they handled it, obv I was fully in command if need be, but I let them get on with the whole thing usually having talked them through the possible scenarios etc on the flight out. 95% of the time it went well. The 5% of time it didnt was if the weather was bad and VOR/ILS in IMC was required, but even then I was impressed at the levels of competency of some of them. We arent talking EU or USA and I am talking either seat, flown by a 250-500hr TT pilot with maybe 50-100hrs on the C++ and the rest on a Bell47 and R44.
My experience with one UK operator offshore was I was ONLY allowed to fly from the left hand seat. I changed operators after 3 years and immediately either seat wasnt an issue. This was purely a company decision.