The whole pipe has to be replaced so to save dicking about you just stick the grinder in there with a sliting disc and lop it off.
Even if you get it loose with mucho Plus Gas & heat, the unions still fecked and would be a total bodge to even put it back.
Even if you get it loose with mucho Plus Gas & heat, the unions still fecked and would be a total bodge to even put it back.