On the elderflower syrup, as I had quite a bit (in plain old water) today:

It comes in a smallish glass bottle, a little smaller than a 20oz soda bottle. A little bit goes a fair way: when I do it over water (as shown by Elise), you do somewhere between half a centimeter and about 2 in the bottom of the glass, and the rest water. Very light refreshing taste.

They also do lingonberry.