UK Wine Tax Calculator does do, simply and effectively, is tell you how much you are giving the Chancellor of the Exchequer every time you buy a bottle of wine.
Entering the bottle price and alcohol content, you can see that the cheapest wine on Tesco's website, the 2006 Silver Rock Chardonnay at £3.12 per bottle is 85.9% tax and duty! Just think what rubbish might lie underneath the cork! This app is a tool, nothing more or less, and it does the job perfectly well. To add a bit of fun, it could have included other countries or states as an option to compare how much we are horrifically taxed in comparison to our EU neighbours, but that might come later. In the meantime, it is a handy little tool.