I've tried shit loads of WD, heat, breaking the sensor clip to free up more of the pin but my mole grips cant grip enough

Its stuck fast, any ideas?

I cant even snap it to be able to drill it

 

its one time you do need some decent grips

plus gas is a much better penetrating oil ...so maybe try that

then maybe some better grips , these knipex cobra dont slip

 

Yes a good set of mole grips that clamp hard. Get yourself a can of wurth rost off ice, give it a good squirt and then it should start moving! Done a couple of these and you won't get it out without gripping it properly.