For general caravan advice, have a look at Haynes' Caravan Manual by John Wickersham. (should be available at, or obtainable by, your local library or buy on auction sites etc).
Many appliances have been fitted to caravans by a number of different manufacturers, and information can often be found on the websites of Thetford, Dometic (Electrolux) and others.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.