20th July 2016 17:19
I emailed An Post to get clarification on this as the lady in my local post office told me I would have to pay extra postage as our invites are being posted in August, yet I have all the wedding stamps bought. Their reply was that "the wedding stamps you have purchased are fine to use as "N" covers the national rate and will not require any further stamps".
Just make sure your invite isn't too heavy and needs to be sent at a higher rate.
Can't wait to have ours all posted!