Thanks for suggestions, had been thinking about €50 or so for a gift/ voucher
Only married two months and if guests we asked but couldn't attend give us a gift of 50 euro we would have been very happy with it.
Did you have Wedding List in one of the big stores? A friend of mine bought a gift of a wedding list in a well known store in Dublin for a wedding that she was invited too. She went to the wedding. Some time later she thought in strange she didn't received a thank you card from the couple. As she was very friendly with the bride's family she ask the bride's mother about her gift and if they received it and it turned out the couple never received her gift. The store made a right cock up of the gifts for her wedding. So be carefull where you have your wedding lists.