hi lads, the pinch bolt on my b5.5 passat is seized

and the net has sheared off and i cant get it removed

the nut end of the bolt with the thread on has been drilled out past where it was threaded to but still wont come out, even with hammer and punch
have cut the bolt through the gaps of the bit the bolt goes through - just given me 2 pieces to remove really

soaked in wd40 and plusgas for 3 days now - not done sod all
the head of the bolt is nigh on impossible to get a rachet on - or i'm dumb and not using one of the attachments i should be or something. but using just a rachet, dont have leverage/strength to crack the nut off. room is real tight so cant grip properly to use full strength - not that i've much

drilling isnt getting me anywhere - whats the best sort of drill bit to use? hss sds it doesnt make any sense to me tbh