Samples, my dear boy, buy her an entire bouquet of high-end samples wrapped in ribbon. There is no chance in "hello" that you're going to find the perfect fragrance with one roll of the dice. Just imagine her opening a package containing a beautiful cut-glass dish brimming with 15 different fragrances to enjoy over and over. Fifteen different experiences available within more than 45 applications. There is no better way than this to find out what she likes.
Now, I'll rely on the girls over on your side of the puddle to chime in and tell you where you can order samples. You can ask the shopkeep to help you select what's most popular.