It is unlikely that it will be cancelled, but it doesn't hurt to check ferries schedules and other flight options for same or next day, but I would not book anything. I assume you have a flight home the next day and you really need to be home the next day? Otherwise I wouldn't worry about it. If that's the case, perhaps a back up flight home with Avios for the day after that you can redeposit for free may be an option, assuming this is available/workable.