I was at the HP distillery last october. There i was told the 15y old wasn't available in the distillery shop anymore. Sold the last one three weeks before. The last batch of 15 y has been bought by Sainsburry's they told me. It will not be produced again. So if you want to try, buy now. I have tasted it. It's o.k. but not real special. I was told it mostly a mix of 12y and 18y. I definitly prefer the 18y. But if you enjoy the HP buy it, it won't be around that much longer!