neff oven u1721n2gb?

I am trying to remove my element to replace it. I have removed all screws and disconected the wires at the back but the element is held on by a clip situated at the top of the fan blades. the screw holding it is partly hidden behind the fan stopping me getting a screwdriver into it.I cannot get the nut off the front of the fan to remove it.on all the other elements the clip is to the right of the fan with easy access to the screw.What do you advise. many thanks. ken.