Original sentence: Prior to that date it was an informal consortium of the six north Wales counties (Anglesey, Conwy, Denbighshire, Flintshire, Gwynedd, and Wrexham)
Edited sentence: Prior to that date it was an informal consortium of the six north Wales counties (Anglesey, Conwy County Borough, Denbighshire, Flintshire, Gwynedd, and Wrexham County Borough)