And there is a reference here to Back Lane (now Spurgeon Street) https://www.essexarchivesonline.co.uk/Result_Details.aspx?DocID=994567 though from the position of the name in the image, it might only apply to the properties along that side of the building running into Spurgeon Street and not the quay facing buildings (though they think they are on Spurgeon Street, so I'll change it to that).