I don't know of a DVD but .....
If you have read "Trout from a Boat" then you will have picked up more than enough info on the subject to get going and catching well , next thing is to just get out there and learn first hand . It is by far the best way to learn IMHO , just don't get stuck doing the same thing day in day out , try to think about your fishing and just adapt to the situation as you go along .
Do you fish alone ?? Another good way to learn is to get days out with some lads that have half an idea what they are doing .....
I believe Dennis is working on another book at this very moment