I haven't the hardihood to read through all of this but I'd like to chuck in a thought on some of the early discussions about Walker Shore (fanciful, IMO, theories about sewers and the banks of the Tyne etc.) A glance at the map will show that both Byker and Walker are miles from the sea. So it's not likely to refer to a mine on or under the sea shore. Back in the 17th-19th century Byker, Walker and the area between was largely open countryside. I have always heard the name as Walker Shaw. The dictionary defines shaw as a wood or wooded area; so Walker Shaw becomes a mine in woodland. Makes more sense to me.