Ok, I put the bug in with the sugar water and stuck a condom on it.
It did nothing for a couple of hours then started to rise, to 45. degrees then stood proud and tall on top, at which point I put a little hole in it with a pin. It deflated, then filled again, now not quite "erect" but at about 5 past midnight. How will I know when the fermentation process has done its job and its ready to drink? When the condom falls flat against the bottle again and loses it's.....erm...for want of a better word....stiffness?
When do I call this thing ready to drink?