ClashCity - yes, I agree, and we analysed a few seats up thread which showed this. But, I think for those one time Labour voters who did go Tory the "and he didn't let them down", is going to be the hard part to deliver.
Given that he is going to have even less of a clue than Corbyn as to what makes northern Labour voters tick what will he have to give? OK he's latched onto the NHS, he says he is going to prioritise this, so it will just need one hospital to close for this to be exposed. He won't be able to conjure up 50,000 more nurses in time by training UK staff.
Get Brexit done - so ill defined. But people are absolutely pig sick of austerity so they will need to see improvements of some sort. What exactly? If he does throw money at problems like crumbling schools and transport the southern moneyed Tories will start squealing that why should they pay for these people who aren't really Tories?
But having lived in a Labour 'heartland' for a short while some 40 odd years ago, I do feel that they did take their electorate for granted and I am not convinced that they changed. I would also question what Blair's New Labour did for those areas ravaged by Thatcherism? They had 13 years. Actually, I believe that they did do lots, like put more money into education, but that goes almost unseen when the local heavy industry employing thousands closes.