Bottle training

Elliott doesn't like the bottle. I have 5 1/2 weeks until I am leaving him for 24 hours to go to Auckland. I'm getting pretty worried. I've been on daily bottle training now for 8 days and 20ml is the most he's taken. I'm just hoping it'll click one day soon. Having done a bit of research he can be diagnosed as a stubborn baby (as opposed to nipple confusion) so he knows what to do, he just doesn't want to. It's a battle of wills!