I was struggling with the spinning wheel so much that I caved and bought a drop spindle which came in the post yesterday.
I've been playing with it yesterday afternoon and again today and the drafting is finally beginning to make sense. I'm actually producing something that bears a slight resemblance to wool - sure it's a bit uneven, and it's overspun in places but I'm getting the hang of it. A little bit more practice and then I'll try again with the wheel. No pictures of the spun singles - too embarrassing and also not enough light - maybe once I've plied them.
I'm feeling much happier about the whole spinning thing now, I was beginning to think I'd never get the hang of it!