Aw, thank you all! That's very helpful, I suppose I could have Googled it more, but when I tried, there was so much waffle, I gave up, and thought of asking normal chums, like here!
Now, had it been a 48Hour Turbo Yeast for strong wine, I could have bored everyone for ages..;0)
(We'll chuck what we have - it is clearly not in good nick)!