I didnt have any joy with them Luke, but give them a try.
I set my kit up at first and left it over 12 hours and didnt get any bubbles at all.
Ditched the mix and started again with another set of sachets.......12 hours later nothing, went and bought some yeast, stuck some of that in and had bubbles in under 2 hours.
Now make my own mix...Fill unit to the 1st inside fins with sugar. Then fill with look warm water (not too warm or you will kill the yeast) to a wee bit under the second fin.
Add a half teaspoon of Bicarbonate of Soda and about three quarters of a teaspoon of Dried active yeast. I get bubbles in under 2 hrs and change the mix once a week. Now that I have two units I will change one on a Sunday and one on a Wednesday.
I use Allison Dried Active Yeast (bright orange tin 125g) ,bought it in tesco. Keep the yeast in the fridge.
Hope this helps.