i had the same problem, the struts we're being binned so a set of stilsons round the shaft and and a mate on a spanner on the top nut soon had them off 
+1 This is exactly what i would do.
Put the drill away, and try this method first.
Not sure, had a look at nut and not much to drill at, so thinking of going to a tyre place in morning and getting em to have a crack at it, soaked in wd40 now for what it is worth, would being driving 5mins with nuts loose, but just have to take it easy,
That and I don't have any stilsons,
Would love to sort em tommorrow, so will keep updated!

my dad has air ratchet but he is working, so may have to wait a few days till I'm off again when he is..