Thanks @jamesinc
@24Orient new Nivomat shocks are available but there's no options (at least that we can source) other than Genuine Volvo.
Converting across to a conventional spring and shock setup from Nivomat isnt too painful - rear springs are different, rear shock mounts are different and there's actually a couple of variations on bump stops too. Either is usable, but when you've got it all apart, it makes sense to replace them.
Some Nivomat cars also dont have a rear swaybar but one can be retrofitted.
If you've got any specific questions, happy to answer them, just reach out.