The civil service is worth considering, depending on what you want.
If you are intending to embark on a career in that job - I would argue you are probably wasting your time entering at that level. You will be free of course to enter certain inter-departmental competitions and open competitions and depending on how you get on, you may move up the line. There is fierce competition for positions however, and panels can be very slow to move.
You should also bear in mind if you do get promoted through an open competition, you may not be guaranteed that you will remain in Castlebar. Given decentralisation, you might be moved to a location you don't particularly want.
Work at clerical level can be interesting - but it is often a basic administrative role. Then again, I have come across many staff at that level who work in interesting areas in various teams/divisions where they are fully involved in working on various projects. It depends on what you are doing and the role/responsibility of that particular division.
While you may be overqualified for the role you are considering - you will find that many people in the civil service have third level and professional qualifications.
Working in a family-friendly environment is a positive one, flexi-time is a significant bonus and there is encouragement (financial and time off) granted for certain types of study/training etc. You are also on a transparent pay scale, obtain the benefit of partnership/benchmarking pay increases and will be entitled to paid sick leave from work.
All in all, it's worth weighing everything up and making a final decision on the basis of what will suit you and make you happy.