Believe this ! bt has had mine off more times than a prostitutes knickers go up and downIt's not as hard as it looks. Undo the rear bolt,don't try to lift untill you have gently prised the fairing at the front away from the tank,it will come with a pop as two lugs come out of two rubber gromets on each side,once they are out gently lift the tank at the rear and slide rearwards a couple of inches. If it won't move don't force it as you can snap off the fairing lugs, get someone to hold the fairing out or try moving the tank one handed while you hold them out with your other two hands?? sometimes you have to wiggle it a bit to do this as it is sitting in a groove on the frame each side held by two large rubber bungs.
Once you have it moved you can lift the rear a few inches and prop it up somehow while you disconnect the sender unit ( a connection is just the other side of the frame tube,disconnect it and feed through the frame to free it up) then disconnect the breather pipes and the fuel line/overflow pipe ( a pair of pliers come in handy for the clamps) and you should have the tank free to remove.
Replacement is the direct reverse of this procedure, remember to push the tank as far forward as it goes and the fairing tabs will line up and pop back into the gromets in the front of the tank.