Replacing the element in a NEFF U1721 but having trouble

I had a fan blade that clattered as if it was loose. When I eventually got it off I found it was buckled and it was the buckling that caused the noise, not because it was loose. It took a long time to get it off and I think the reason it gets stuck was that the spindle has a flange to which the back of the fan blade gets 'welded' with grease, oil etc. Apart from undoing the nut (clockwise not anti - I used a 10mm socket) the next step is to get the washer off. Prise it of with a flat bladed screwdriver. After that there is nothing holding the fan on - apart from the 'weld' mentioned above. The fan should spin freely on the spindle but won't because of the 'weld' I tried holding the spindle with a pair of pliers and bashing the fan with a hammer to try to free it but to no avail. What actually worked was turning the oven back on and getting up to speed. I then turned the oven off. The oven was warm but not hot at this stage. Next I clamped a pair of molegrips on the spindle then whilst holding the molegrips firm tried to turn the fan back and forth on the spindle by hand and it eventually moved. I think the warmth might have just 'melted' the weld. After that a bit of back and forth movement got the fan off, however for the last bit my wife was holding the motor to stop it moving as I rotated the fan off the spindle. Yes the oven was out at this stage, on a workmate with the power off. I had a fan blade that clattered as if it was loose. When I eventually got it off I found it was buckled and it was the buckling that caused the noise, not because it was loose. It took a long time to get it off and I think the reason it gets stuck was that the spindle has a flange to which the back of the fan blade gets 'welded' with grease, oil etc. Apart from undoing the nut (clockwise not anti - I used a 10mm socket) the next step is to get the washer off. Prise it of with a flat bladed screwdriver. After that there is nothing holding the fan on - apart from the 'weld' mentioned above. The fan should spin freely on the spindle but won't because of the 'weld' I tried holding the spindle with a pair of pliers and bashing the fan with a hammer to try to free it but to no avail. What actually worked was turning the oven back on and getting up to speed. I then turned the oven off. The oven was warm but not hot at this stage. Next I clamped a pair of molegrips on the spindle then whilst holding the molegrips firm tried to turn the fan back and forth on the spindle by hand and it eventually moved. I think the warmth might have just 'melted' the weld. After that a bit of back and forth movement got the fan off, however for the last bit my wife was holding the motor to stop it moving as I rotated the fan off the spindle. Yes the oven was out at this stage, on a workmate with the power off.