SJS
Hall of Fame Member
You said it.Tanvir looks exactly like a natural right-hander who has taught himself to bowl left-handed.
To me he is the mirror image of so many right handed inswing bowlers from my playing days. Its just that left arm bowlers never saw any point is learning this more demanding (physically) type of swing when they could naturally swing it in and cut it away from righthanders.
I was fascinated to watch him.
I suspect that once the novelty wears off he might not be so devastating but he is a fine bowler. It will be a big strain on his body - this action. But any efforts to change it might completely destroy his effectiveness.