Hi Ian and Judy
We had a boisterous sail from Bonaire to Puerto Rico last year during which my daughter was tossed onto the toilet in the forward head and cracked 3 of the plastic (?PVC) mounting lugs of the toilet base. I ordered the Jabsco PN 37004-1000 toilet base from Amazon for $139.00 US and received it in a couple days. It fit the existing hole pattern perfectly. The bolts screwed into mild steel backing plates that are imbedded in the fiberglass much like the lifeline stanchion mounting system. I just backed out the bolts, mounted the new base to the porcelain bowel (the base comes with a new mounting gasket as I recall), re-installed the assembly, then realized I didn't have clearance to screw in the outflow hose adapter that has the "joker" valve in it so demounted the base etc, attached the outflow adapter, then re-set the base.
I just now searched Amazon and see the correct PN listed for $116.00 (cheaper than what I paid). Hope you can procure one via Amazon in Greece.
All the best,
Gary S. Silver, M.D.
Amel SM 2000 # 335
Puerto Del Rey Puerto Rico (on the hard)