[HB] Nowt Welsh at all, I'm sorry to say. Although I have tried and dislike laver bread, I would have bought any (or all) of the other items that you mentioned. I would also like to mention that difficulty my Irish father-in-law suffers in trying to find me a St David's Day card, on the back of my always sending him a St Patrick's Day card. Sceptics, note - he managed it once, so such cards do exist!
[ZK] You need to get in touch with this fine body of people. Who will no doubt explain that it was, of course, the Welsh who discovered America in the first place, a fact disputed by Native Americans who unaccountably reckon that they got there first!
[BM] I think you need to write to these people and explain to them the error of their ways. I've lived in Ireland and the U.S., and while I agree that abominations like green beer are a U.S. invention, it's simply not true that Patrick's Day is not celebrated in Ireland.