Vermin:
Could I just ask again how much success people have had using DVD as a learning medium?

It's probably a little unseemly to advertise oneself in this context, but may I point you to: How To Play Davy Graham's "Angie", which I posted on YouTube 3 years or more ago.

If you read through the comments, it's fairly clear that it's helped several people to play this tune. I've also sold a fair few number of DVDs on the strength of this and similar videos. One of the reasons is the animated finger positions that I use to illustrate the tune in slow-motion.