not got round to greasing the propshaft on my td5 yet.
but all of the grease nipples i`ve done on other vehicles have just screwed into whatever your greasing. depending on how its sheared off, you still might have a 8 or 10mm(lr`s might be different) spanner size nut to undo. if its snapped off flush, then an easy out should do the trick. really can`t see why you can`t carry on driving though.