On the Bobby sweater, it says L - 43-46" chest - website
But on other sources it says XL - 42 - 44" - some John Smedley lit
So I'm not sure which one to believe? How has this fit you? I'm 6'2", 210 lbs (athletic) fit
Curious, what is your suit size (US)? 40R? 42R? 42L?
I'd say your size depends on how you want it to fit. Some people like their sweaters stuck to their bodies like a tight t-shirt. Others like looser fits. I believe the measurement quoted on John Smedley's website is the exact (unstretched) chest measurement. Go from there.