OK, well, you are learning as you go along.The coffee was better than expected. Stevia is not bad. As you say , not good either. But not bad. It is definitely not as potent as the box claims, which I fully expected to be the case. I take 1/3-1/2 TSP of sugar in coffee, and chucked in a whole packet of stevia (supposedly 1tsp sugar equivalent) and it was not much different. It was like if I use cheap shitty white sugar instead of brown cane sugar like I usually do.
BTW, you should feel lucky you don't live in the US. Because US food companies put all kinds of hellacious artifical chemical crap sweeteners in their foods and beverages. Stuff they probably don't allow in the UK.