A year . . . . well, a few months
All episodes are covered here, but, sadly, they have been savagely cut to fit onto one DVD.
I was surprised that the entire offering lasted only 4 hours - must have been only 30 minute episodes, I thought. But, while viewing, I realized the programmes had been cut severely.
The main themes of each episode have been kept, but much of the connective content is cut out.
Disappointing - maybe the other offerings have greater content - I advise checking total duration times on each item to avoid losing too much content.