Anyone know how to actually remove the sender unit from the tank?

I have lifted the rear floor & seat & gotten to the top of the tank, but not sure how to actually remove the sender unit. Looks like a 45mm nut on top of the tank with the sender unit in the middle.

Any advice is appreciated.

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David Hendy
'97 Renntech E60RS
'97 GMC 2500 Sub' Diesel
'95 E300D
'88 300TE
'88 250TD
'84 L/Rover 109