It is in fact only available in German. This is because it was produced by BR (Bayrischer Rundfunk - bavarian broadcasting) for German TV, and not a translation of e.g. a BBC documentary, like the Arena special.
I am not sure when and where eactly it was filmed. Obviously in London and in the US, but possibly also some parts in Germany. Should be January/February '79, the US part seems to be from late March '79 I guess.
The rehearsal of Down to the Waterline might be from January 4 (where our date list says rehearsal in Greenwich). Strange that the greenish 'black volume knob' pickguard is on the maple neck Strat here, as it was on the rosewood Strat both before (December '78 UK tour) and after (on the February '79 gigs the maple neck Strat had the white pickguard without the black knob) - and it was on the maple neck Strat again from March '79 until late 'November '79.