Over the past year I replaced the pump assembly on my Raritan, it was a simple operation and less expensive than a new head. The parts that wear are the various seals and the pump assembly. The base and the bowl just don't wear out. I also replaced the "marine" bowl with a standard household bowl. That was a nice comfortable upgrade.Am I correct that you have done a 10 year on the hard refit of a 25' boat, are now stuck in place due to a "bargain" toilet, and you are a professional with 50 years experience ? I think there is a lot we can all learn from your situation; I've been trying to decide whether to re-build or replace my 12 YO Raritan.