The phone polls will be closer to the truth, you'd think. They were better than online polls through the election campaign. Whether that stands for a referendum I don't know. It would be interesting to look back at the Scottish independence polls.
The current consensus seems to be that leadership ratings are much more accurate than voting intention numbers. If that translates for the referendum then I don't see how the leave campaign isn't fucked unless Boris Johnson leads it, which I don't think will happen. Even then I'm not sure if he's more trusted than Cameron. Farage should be avoided; some polls have him as more disliked than Corbyn, which is some going.
I suspect Cameron is playing a blinder with his current 'deal'. It all looks like a set up ahead of his next round of negotiations so he can come back with something slightly better and claim he has listened to the British people and persuaded 'the Europeans' to go further. We shall see.