Then I spoke to a friend on the phone in the early hours. We chatted about possible lines of attack on some puzzles; suddenly we're unblocked again and a few of the puzzles look ever-so-slightly vaguely crackable eventually. The whole process would be much more successful and much more fun if we had got our act together and succeeded in getting the Britfolk into the same place at the same time - ideally one with about four computers with net connections - but we didn't manage it. Oh well.
Have fun in Oxford, folks!