I tow a twin axle Lexon (max weight 1600kgs) with the 110PS diesel Galaxy (weighs in at 1860Kg)no probs. The Sharan is basically the same car and should tow OK.
Unless its the low powered 90PS version the galaxy is a superb towcar. I tow a twin axle Lunar no problem. I towed a 17ft challenger before this and he car didnt have to try.