Ah fair enough Soak it in penetrating fluid then short sharp hits with a hammer put a nut on the end to protect the thread, I dont tend to heat it if I can avoid it Shocks being pressure vessels and all
I think the spline is like m16 on those I cant remember off hand and laser do the spreader tool for about £5 so well worth having, a good hammer and penetrating fluid if you need actual sizes I've got a stripped mk 4 in the garage atm so dont mind checking.