Thats a valid point Lynn...... Martyn do you have the full shroud assembly on the fan ? without this the fan wont generate the suction it needs to draw the cold air through the rad and into the engine bay.
As for the heat, it was baking hot in the rear compartment of yours when we were cruising back home from the Armed Forces day.... it was a welcome breeze when i sat on the ammo tins so i was a bit higher up.... mind i reckon the boys who landed in Italy 1943 welcomed the warmth through the cold november / december ops..... i recall from reading a letter my grandfather had sent home, it was one of the coldest winters on record for Italy that year.
swings and roundabouts as they say.