Hi!
I just caught this and wanted to say hi! I'm from Northern Ireland too and did my PGCE at Coleraine and then a year at Methody and one at BRA. I'm now teaching in Costa Rica!! I had only taught L6 at MCB and BRA and had no IB experience but still got the job

I wouldn't worry, I think it is definitely more based on interview and obviously A-Level experience will help. In terms of preparing yourself personally I would recommend READING. I know I spend a lot of my time now reading history books to get the level of depth I feel is needed to teach IB. I especially recommend anything by Overy. I would make sure you are familiar with the Dictator's and WW1 and WW2 as a lot of schools seem to do these options. All the Irish/British stuff is kinda useless though, lol. However, as you are undoubtedly really busy as it is you probably shouldn't worry about it at all! Aiiiii, I'm babbling, it's Friday and exams start next week.
I'm
rachelloughery@hotmail.com if you want to get in touch. I'm really a bit over excited to see someone from norn iron on here!