Lift the rear seat to access the the black cover on whichever side you think is leaking . Undo the 10 mm bolts and remove and you should see if there if fuel on the top of the tank. Using a large screwdriver and hammer , tap the collar anti-clockwise to remove and carefully lift up the pump/ module just enough to remove the seal. The seal has a v shape that pushes into the tank hole then push the pump back down to hold it in place and refit the collar. It happened to my diesel when I’d replaced the sender and hadn’t tightened it enough, so when I brimmed the tank it was pouring out !
