Welcome to the forum.
My speculation is that the factory has not provided an access port for replacing the part.
On my 2000 380DA there is not an access port. On my boat the two options for this repair are for me to create this access by drilling at the correct location, or to remove lots of stuff and slide the tank aft into the engine room.
If this was the only problem, then I would carefully drill, but I would discard the "measure twice, drill once" rule and instead provide additional measurements.
