iPhone app doesn't yet have booking capability (though supposedly coming soon), so unless the android app already has this functionality now, this must be a mobile site issue (in web browser) rather than an app issue.

I have recently successfully booked a r/t coach ticket on the mobile site using my iPhone, but that data point is probably of little relevance to your issue.

FWIW, You might be better off starting a new thread rather than resurrecting a 2 year old thread, as this is likely not an issue that has been going on since the original thread was active (unless o/w FC ticket bookings are really rare!)