If its a carver inlet and you pump detaches then its a MK2 or MK3 and the covers are readily available we sell them at £6.99 at www.weekendleisure.co.uk. They come with new plastic pins for the top they also come in ivory or white, ivory is the most popular.
Truma took over Carver in 2000 so the newer cover are often marked Truma.