Just got home from the Prince Charles screening myself. It was also my first time seeing the film so am not in a position to confirm for sure what was or wasn't in the film compared to other versions, though was trying to take mental notes to report back here. A few notes on the print:

- At the very beginning there was a very brief glimpse of an MPAA "PG" card, no sign of a BBFC one.

- This was followed by the Saul Bass Warner logo, and then the Buck Rogers short excerpt.

- The print was quite pink (very similar to the 16mm colour correcting samples on the previous page of this thread), but more or less in pretty good nick, quite a few splices and scratches around reel changes as you'd expect from a theatrical print of that vintage.

- Based on thxita's translation of the extended Sen/kids scene, from what I recall that extra dialogue was not in the print tonight, just Sen talking about "combined primary economics".

So from what I understand it was the 1977 version. Hopefully someone else who knows the film better than me was there too and can chip in, but am reporting back just in case! :)