Thankfully, the judge seems to have seen through the nonsense and told them it's been served, so get on with it.Then serve it at their offices at the time of the hearing. They are irrefutably instructed in the proceedings at that time.
Or via email, maybe; at any time.
Without knowing the procedural rules for the jurisdiction it’s hard to discuss with any real authority, but it’s hard to imagine justice being allowed to be defeated just because someone lives in a castle. It would make a mockery of the civil justice system. No self-respecting legal system will allow someone to avoid service in this way, at least in the long run.
Within our civil procedure rules there are alternative methods of service once the conventional ones are exhausted.
It’s not like the **** can say he doesn’t know about the essence of the claim; he did an interview about it on Newsnight ffs!