It would seem odd for the lyrics to be walk ashore and for others to mistake it as Walker shore - since Walker is definitely an area of Newcastle. It seems more likely that some Geordies told someone this for a joke and it stuck...

I once heard (many years ago) someone singing a parody of this song - called Byker Wall. The Byker Wall is a very famous piece of 60's architecture in Newcastle that they have been threatening to pull down.