Thirded so long as we can drop the border down to include Cumbria, Northumberland, and Tyne & Wear... maybe North Yorkshire, too. I'd love to be Scottish if they'd be happy to have us!
Manchester should be fine, and Wales is a given. Who wants to pay £4bn for a project which only benefits England?
We may need to include Merseyside, Lancs and Cheshire just to have a land connection between New Scotland and Wales so we don't have to consider touching England.