Yes Mike that would explain it, however, I thought I've swapped bowls before but will definitely try that.
Thing is, as I was trying different float heights, I left out the gasket for ease and even had fuel coming out of the gap between the bowl and carb body as you'd expect with no gasket, which seems to point to very high fuel level even though the level in the sight tube remained below the line? Scratching my head.
Thanks, Peter.