Returns from Republic of Ireland to UK

I'm based in UK, FBM, but I get quite a few orders from Europe which I've not had a problem with....until now!

A customer from the Republic of Ireland has requested a return of an order but I'm not sure how to accomodate this. Am I right in thinking Amazon won't automatically create a return lable for international customers? If that's so, what's the best way to get a returns lable to the customer? Only thing I've found is to buy a lable from An Post (Irish postal service) and email it to customer. Is this a good idea?