Been reading Alastair Moffat's great book on the Wall. So much of what he says is new, things i had never thought about. For instance the Wall wasn't just to keep the Scots out. It was also to separate the tribes in the North from those in the South.Stop them plotting! Thats why the Vallum is on the south side of the Wall.Always puzzled over this but now i know.
Also there was a sea wall, well perhaps more a road and forts down the west coast , possibly as far as Ravenglass.
Also the fact that Hadrian was a complete fan of the Greeks.