Well, I could have simply replaced the deck plate O ring, extracted the fuel from the tank and called it good but I think we all know I can turn something simple into a three month project. And I did.
As previously mentioned, I replaced the 42 year old factory original fuel fill deck plate with an exact match to the plate I installed with my secondary tank for uniformity of O rings and appearance. Sounds simple enough but I had built in a problem accomplishing this when I installed the secondary tank 15 years ago. The tank prevented me from crawling into the space to access the fuel fill hose clamps, under deck mounting nuts and ground wire. There is a cockpit seat hatch right there but no one has arms long enough for the necessary reach. The left picture shows the old fill plate in the center of three, the right picture shows its replacement.
Out came the Sawzall and an access hole was cut in the coaming/cockpit seat back. It worked great, access was excellent. When finished I filled the hole with a coaming compartment and a matching one on the opposite side. Prior to their installation I disassembled the compartments and painted them with the same paint I used on the deck to ward off the typical UV yellowing plastics go through.
Today I did the final fuel polishing through a new filter. I replaced it when done and brought it home to inspect the contents. All good.