I haven't got my dvd set any more Vic - I flogged it to finance the new BD edition! As far as I remember, the extras are pretty much the same, though there are a couple of differences, including a superb 112 page (!) booklet by Andrew Pixley, detailing the creation of the series and a review of each of the first series episodes. Here's a scan of the back cover for full info.
If you only have the dvd set, I can't recommend this enough. Apparently, the only episode they weren't able to restore to HD was the first one. Otherwise they look stunning. Believe me, you've never seen them like this before!
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