We’ve got an extension which was built earlier this year. We were happy with everything until the weather started to get cold and now we get a freezing draught coming from the Veluxes. The draught seems to be coming directly from the area near the handle, where there is a vent. Does anyone know if this vent can be closed or if there are any other suggestions to make the room warmer? The room is currently not much better than a conservatory!