All done now. Acecarparts on eBay had the springs at £44 for the pair for the KYBs. Unlike my old Astras, you do need both wheels off and the car supported to get enough swing on the rear arms to get out the springs. The Astra could be done one side at a time. Whole job took about an hour start to finish, including clearing up.
Gentleman the Voyager has now departed and I would like to thank all of you that have offered advice and a few laughs over the past couple of years. You never know I might return in the future with another beastie but now I’m playing with a Quattro Avant.