I was going off this from the EU:
3rd poorest in Northern Europe on there, I guess depends on what measures they're using. I love County Durham, but the fact that most of it is factory towns and mining villages where the industry died out and was never replaced definitely shows. The bright side of that is that it means there is a lot of affordable housing left over from when there used to be jobs. My village is about 2 miles from the city centre and average house price here is less than 100k so if you get a decent job you're laughing. Funnily enough, my parents lived in Oldham before they moved up here for the lower cost of living.
If you want posh places in the North, York and North Yorkshire generally would be my first thought. Northumberland would be another, but the super posh bits are probably balanced out by the likes of Cramlington and Ashington.