So, finally, after months of phone calls by myself and the authorized dealer to the factory Dometic has shipped a brand new shiny unit to replace my excessively noisy one under warranty. It sits in it's box awaiting installation next week. They should have read my tag line in the forum then realized that never mess with a stubborn Yorkshireman. We never go away. Will keep this thread updated as to the result and what, if any, improvement results.
Keith