Right, this is the final stage. My ferment has had 14 h worth of final growth period and looked like this, at 7 am this morning:
OK, so I had a sniff before I took the photo and some of the air came out, but it was bulging just like in Stage 3. Generally, it still smelt more "off" than alcoholic and sweet, but I will persist. Into the fridge it went and when I checked it this evening, it has bulged again, so I hope it doesn't overrun it's bowl or the fridge will burst.
I did succeed in drying the left-over ferment from stage 2 and whizzed it last night. Very noisy and while drying it, it smelt again, slightly off, even Lundulph commented on it. So the likelihood of making a successful bread is dropping I'd say. Still, will give it a go.
It's all now in a big jar, labelled as Dried Sourdough 05 Nov 2009. My plan is to try the first half of the ferment on Sunday as per Richard Bertinet's recommendation, then do a second lot next Tuesday, when it is more sour. Then that'll be it and I'll revive the dried stuff. That should see us to Christmas.