Hayden, thanks for such a quick reply. It’s good to hear that your replacement sender screws down into the same/original holes. I’m based in the UK but it looks as if I can get a similar fitting from Wema-UK, though as European and American senders have totally different resistances the gauge may need to be changed to suit.
Do you recall whether the original fitting had a cork float on a lever arm like I found in the water tank?
Andrew