The case can't simply be transferred to NI. It would have to be struck out and then claimant would have to decide whether they want to issue a new claim, out of jurisdiction. The court is unlikely to just do that because the claimant did not err, you did.
At this point, you have four main options:
1. Ask the court to strike out the claim without making a formal application. This can be done by sending another email to the court, pointing out that the PoC are defective and asking the judge to strike it out based on the defence and the case law already provided. This doesn’t cost anything, but the court might not act unless a formal application is made.
2. Prepare for the hearing on 6 August. You should check with the court whether you can attend remotely, since you now live in Northern Ireland. If the hearing goes ahead, you should prepare a short argument explaining why the claim should be struck out due to the poor PoC and the lack of proper notice.
3. File a formal application (N244) asking the court to strike out the claim. This costs £313 and would include a witness statement and a draft order. It forces the court to look at the issue, but it’s not cheap and might not be necessary if the court is already considering the problems with the claim. You can ask for the N244 fee back, but there’s a real risk the court won’t award it because of your failure to notify the court of the address/jurisdiction change.
4. Ask the court to confirm that the hearing will be held by video link. This can be done by email and doesn’t cost anything. It’s a practical step to make sure you can attend the hearing without needing to travel to Manchester.
The best course of action right now is to email the court again, asking for the claim to be struck out and for the hearing to be held remotely. If the court refuses to do either, then you can decide whether to go ahead with the hearing or file a formal application.