Short of sending them to Heasmans, there's a mob in thommo that I wouldn't recommend that was a Bilstien dealer back then and he tried to tell me BC coilovers are "great" - truth is they're garbage especially roads up in Norfies.
So yeah, Heasmans or Fulcrum (dunno if they're still selling Bilsteins now, I asked them earlier this year and they do).