Going back through this thread there’s been a massive variety of experience. I started the process in early March and my licence was ready in Sep but without the TRE certificate. That took til Nov to sort out by which time the IAA office was closed and unable to exchange. They are now open part time and my licence is on its way to Dublin as we speak. At the moment once a licence is ready the exchange seems to happen quite quickly. I have no insight into how long the actual licence takes to be created.
emails can take more than a week to get a reply. It’s very frustrating but I’ve just had to wait. I think you’d need a very good reason to go through this process as a Brit (in my case because as TRE I need to be able to sign EASA licences).
Good luck