This is a fantastic reference site for adventurous consumers as well as the pro’s for which it was originally intended. But you have to invest in ingredients, or maybe source alternatives on the Internet.
Of course, most top bars create their own infusions and custom flavourings that are impossible to replicate. Importantly, you only need one gin and Tanqueray is as good as any. If you are tempted to buy a second, buy some Green Chartreuse instead!