Yes you are on the ball there, as I was recently told at a scale event that all model Tiger Moths overheat because the propeller rotates the wrong direction.
The cowl on a full size Tiger Moth was designed for a Gypsy Major engine which rotates CW, on a model the prop rotates the opposite direction more or less creating a vacuum at the front opening.
Hence I have modified the baffles and will see how that goes. I did think it got hotter with the baffles so this will open up the side of the fins.