Ian, if you have done this or it is obvious I'm sorry but
Check for tack welds holding them in, then grind them off.
Support them properly, Find a lump hammer and belt them hard, don't P155 about tapping them or hitting them
Try heating the wishbone (use gas hob at home) first, to loosen them up. Heating them again later mayl also help getting the new ones in, cos they're a tight fit.
If you have a large engineers vice? and a large socket or piece of thick wall tube use the vice to press them out. If not go back to plan A and keep hitting them or as its late so resort to beer.
I did mine a few weeks ago, once they start to move they'll fall out.
Good luck.
Mike.
NO PIES CAKES OR BEER LEFT IN THIS VAN OVERNIGHT.
Member Number 3787