Thanks! Sylvester. I think I'd already considered most of your points. The boundaries of kingdoms in that period were flexible, and names changed on a regular basis. Hence, Brense - Reghed - Cumbria - Northumbria, seems to be the progression of this neck of the woods. I just think that with every minor king producing his own coinage, at the time, there should have been some sign of coins from here! I don't think any ruler here would want to be left out!?! I suppose mis-attributed coins is the favourite answer.