It looks like a Thetford "Bravura" to me. The curved piece under the foot pedal and the general shape is the same as the one I put in my Argosy 20' a few years ago. Mine had a manufacturing defect and Thetford replaced the bottom seal you have which is leaking. They sent me the part, and I put it in. This was quite a while ago, but as I recall, once the toilet was removed (bolts under that pedal cover and in the rear I believe) the slide valve on the bottom just unbolted and could be replaced. However, that is very general information from my fuzzy memory, but I don't recall that it was a huge job. The Bravura is still made and marketed. You might find the cost of a total new one was close to the repair parts cost. I would check first in any event.