Conquer Club

Does anyone know if that one-way attack wall on the British Isle's map, also hides your North England armies from opponents on the other side?

If you do not control or cannot assault or bombard a territory, it will be hidden from you in Fog of War games. So yeah, if you control, say, Lothian & Borders you won't be able to see Northumberland unless you have some other territory that borders it.