Thanks everyone for your replies.
I have no major symptoms at the moment, except slightly raised readings on liver function test which I believe can be caused by the stone irritating the bile duct from the liver.
I certainly would not want to be incapacitated on a flight, my AME said he would be more concerned with that if I had small stones, however with just one, at the size I have, it is too big to move down any ducts to cause incapacitation.
Cheers all.