First Active no longer exist. They are now branded as Ulster Bank who are owned by RBOS.
Your money is safe unless Lyolds Banking Group/RBOS also goes to the wall.
It is possible that if Ireland defaults, which I think is unlikely, that Lyolds Banking Group/RBOS would not also go to the wall as they are largely owned by the UK govt. Hence, deposits with these banks would not be impacted in this situation.