Undertray screw removal

[Scooba_Steve]

Went to do a gearbox oil change on a mates F30 and one of the undertray screws broke. The 8mm head spins but must be rusted in, as they are the same as used on our cars has anyone got any tips for removal? I couldn't get mole grips on the washer as there is not enough room.
Is drilling out the only option?
I thought about using a dremel to cut the head off then cut a slot for a screwdriver.

[Chris_D]

If it's a diesel F30, pump it out with a PELA pump
If petrol, I'd drill out the bolt... easy enough to replace.

[Scooba_Steve]

Anyone removed without drilling? I'd like that to be a final option as the thread isn't very thick. I've not been able to see behind and wonder if it's the clip that may be broken?
I don't have a pump to suck out the fluid, and would prefer to drain anyway as the box has both plugs.

[G600]

If the head is spinning it's got to be the nut on the other side that's the problem, they often split away from whatever is supposed to hold it in place, try and grip it with pliers or something while you turn the screw

[Scooba_Steve]

I can't tell what's behind it from RealOEM but think it might be one of the clip type screw receivers. Trouble is that the tray is securely clipped in so getting behind wasn't possible...

[G600]

I can't tell what's behind it from RealOEM but think it might be one of the clip type screw receivers. Trouble is that the tray is securely clipped in so getting behind wasn't possible...

In that case if it was me I'd grip the head with pliers or mole grips, drill off the head so you can remove the undertray then replace the clip nut.

[Scooba_Steve]

Thanks chaps, gives me some ideas... Simple jobs that never are!