Hi, as an ex-member of 7010(VR) Sqn RAuxAF I might be able to shed some light on the Int side.
Depending on whether you join 7010 or 7006 you will have to travel to the mainland as neither squadrons have any locations in NI. Both squadrons are headquartered at HQ Int Reserves, RAF Waddington near Lincoln. 7010 work from RAF Marham (Norfolk) and RAF Wyton (Cambridgeshire) and from memory 7006 are located at various other UK RAF bases.
You would have to complete Basic Reserve Training or Reserve Officer Initial Training and then trade training, again both on the mainland. Once through trade training attendance is or was one weekend per month plus fifteen days continuous training every year. On the plus side you get paid for travel but the big questions are (1) can you make the duty commitment, (2) would the amount of time in transit be worth it and (3) could you fit it in with the rest of your life. Hope this helps.