Why exclude Northumberland? I noticed that the "EFDSS Hardcore English" CD didn't exclude any NE music either. I must express extreme anger at this normally unarticulated but deeply held belief expressed by many folkies that, say, the Cotswolds and Sussex and East Anglia are the "real" English, but other portions may be less so. Shropshire is too Welsh, Lanmcashire is too Irish, Cumbria and Northumberland are too Scottish. I might say that Sussex is too French, for that matter,but I wouldn't: Scan Tester and Billy Pigg are both great English musicians, and I am not going to rank them for Englishness. Northumbria is close to Cumbria, and far from Hampshire. But they are all English, all separate in one sense, and together in another.
But, does Northumbria have more slow music than Sussex? Yes, assuredly, in recent history anyway. But both have lots of sheep.