I haven't posted for a while so here's an update.
Yogi has matured into a very nice starter. Smells yeasty and remains active.
I attempted my first sourdough loaf the other day and ended up with a brick. The taste is lovely but it's destined to be reborn as tasty breadcrumbs.
Perhaps my mistake was to treat the dough as I do yeast bread dough. It's quite different. The way the natural yeast works produces a dough that is delicate so a gentle touch is required past the initial kneading and rise.
Now that I'm better informed, attempt number 2 is on it's way. I'll let you know how this one goes.