If I recall correctly, at the Bafta's FD were showing a pre-release of the build that gave us the Orbis... then we got that build the week after or something... There's no reason why EGX has an early build of Std Beta 2.... then we get it after EGX.
The Bafta event had the first appearance of the Coriolis station, docking, outfitting and the Cobra Mk III for Alpha 3. We knew we were getting Alpha 3 that week though.
The Orbis station was actually first seen at E3 but post Alpha 4 all dates for major releases were announced in the newsletter.
All of the Beta release dates have been given in the newsletter so it's likely Frontier are still trying to finish off branches of functionality they are hoping for Beta 2 and will announce the date on a Friday consistently. They may demonstrate a dev build for tomorrow but doubt it will have everything merged in that's expected for the Beta 2 branch if it isn't completed.