Do not use an electric screwdriver, too little control. If you can fit something on the screwdriver to give you more torque, maybe molegrips or pliers on the screwdriver shaft, depending on the shape of the handle it may be possible to fit an open ended spanner if it has flats. Make sure whichever screwdriver you use is a good fit. If you can fit an additional lever as above, push down on the screwdriver with some force.
Aerosol usually best.