I’m pretty sure that consumer rights in the uk (and ireland?) are, that you are entitled to a replacement or refund if the goods are faulty or if you were sold the product under false pretences you are entitled to a refund. But there is no law saying that your entitled to a refund if you change your mind. It seems that most shop just have some sort of return policy. I know that cash converters don’t allow refund/ exchanges on any software, and I think game shops only allow a refund if the product is not opened but i’m not sure about that.