we've always used Lurpak since I was a kid. I remember my mum sending me to the co-op to get it and the used to come in huge blocks they'd carve off what you wanted and "Pat" it into a square then finish it off with a different emblem like a buttercup or a cow.
Almost all the spreadable butters are blended with vegetable oils to make them softer. Kerrygold used to be 100% butter, but look at the label, I've recently come across some that has been blended. Lurpack make a lot of spreadables; salted, unsalted, organic, lighter and lightest - all based on butter.