We do have 1/2 fare cards, had a look at the train, it was 250CHF each for the dates we want, flying is 240CHF with airfrance.

Had a look at blablacar carsharing site..nothing up there yet....

Heard rumours that booking with the French or German rail companies can be cheaper, so going to ring them tomorrow, as it didn't seem possible to get prices online....watch this space