While I had a spare moment this afternoon I replaced the fuse holder with the new one.
First open the thing up:
Then unsolder the wires from the old fuse holder:
Remonve old fuse holder and replace with brand new one. Then resolder the wires to the newly fitted fuse holder, making sure that the wires make a good mechanical connection as well as electrical, so that should the solder come undone, the wires stay connected. A must for mobile installations where vibration or corrosion could cause problems.
Reassemble and voila! Working rectifier. Test using power supply and confirm that AC input produces DC output. Job done.
At some point when the weather and tides are favourable refit to boat.
The only missing link in the charging chain is the wire underneath the connector on the stern, which has corroded completely away. So the connector needs removing and connections checking. If everything is good to go, then a short piece of twin-core wire to the existing wiring will bridge the gap.
Then I can finally tick it off my to-do list. Its been on there since September!