Intending to replace fork seals (89 K100RSSE) but fell at the first hurdle. All four horizontal and the longitudinal nuts and bolts fixing the two piece mudguard well and truly seized/corroded with bolts immovable and nuts spinning on their threads. Drilling out the longitudinal one should be fun. Any tips?

I used a dremel tool to cut the longitudinal one in half, the nut in the front half is a square thing and once it manages to turn in its enclosure you're absolutely stuffed. But you can remove the front wheel and attack it from underneath, then use mole grips or something to hold the square nut still in the front piece of mudguard and twist out the remains of the bolt.

As for the horizontal bolts.. No idea. Good luck!

Thanks for that. I was contemplating taking the wheel off but didn't realise I could reach the long bolt from underneath. Will attack it over the weekend and let you know how I get on.