As we go the day after you I had to wait until midnight before I could book our train. Unfortunately I left it until just after midnight, I was watching a Johnny Depp film, so it was already gone 1am German time, and all the cheap tickets for the train I wanted had been bought! We did manage to get a cheap fare on 14.40, which does involve one change but was about 15 euros per person cheaper!

I have to wait until Sunday to book the ticket to Paris, I have got a cheap Eurostar ticket for the journey from Paris to London.