Its Thetford not Thretford
Here is the Thetford website access to free repair pdf downloads I think the Cw-200 is the same not sure but if any probs there is a section on third entry page at bottom of left listing 'Ask Thetford' on-line form fill in your question if you can't find your model in repair pdf section. Ooppsss!!! nearly had a senior moment and left out the list for Thetford site.
UK www.thetford-europe.com
Australia www.thetford.com.au (Even get request from Australian campers)
Australia site has stockist list.
HOME PAGE SELECT ENGLISH {if in Australia forget this selection)
NEXT PAGE SELECT CUSTOMER SERVICE (top line)
NEXT PAGE SELECT USER INFORMATION (left of pic) also 'Ask thetford' is on this page.
NEXT PAGE SELECT REPAIR INSTRUCTIONS (left of pic)
NEXT PAGE SELECT BUILT IN TOILETS [top right of pic]
NEXT PAGE SELECT This is where you select your toilet range. Search alll if unsure of type/range
NEXT PAGE PDF Files You should be in the pdf folder list on your Thetford toilet. Start downloading.
To direct link to the Thetford download site type in the following
www.thetford.eu/web/show/id=51498/langid=42
Don't bother for Thetford fridges they tell you for safety reason to take it to a service centre
Bob
September 2009