From what I can gather, the rating is done in Shannon (think Galway might have been used in the past, not sure what the story is now). I've got to do one over the next while
but got a good bit of advice a while back... if you can, wait til the start of October (changeover to VFR ending at sundown for winter), then you can get the night navigation requirement done on your flight down, and complete the circuit training in one night. Trying to do it all in one night in summer is probably a non-runner in terms of it being fairly bright out til late.
NFC office can be a tad busy at times, or someone might have left the desk for a minute, but they'll fill you in on any questions you might have when you call.