Yes, clubs require membership, I see nothing unexpected there - nor should it be an issue. Expect them to require a check-out flight too, perhaps quite recent, so that you might need to fly with their instructor before every flight since you do not intend to fly every week-end, so to speak.
Mind you that, even if you could find a commercial rental operation that does not require membership, they would still require the check-out flight, and are likely to be more expensive too, both on the plane and on the instructor.
For as little as I know the Irish private flying environment, Weston is indeed the place to go.