It's said that the 80x EMUs will run London to Liverpool, freeing 390s to replace Voyagers on Scotland services, meaning the bi-modes can sensibly be dedicated to non electrified routes.
yea to me the 80x#'s feel more a Voyager replacement program instead of a Pendolino replacement
so prob will be as followed
class 390's to Edinburgh and Glasgow with eventual replacement with HS2 rolling stock
class 807's to Liverpool,Manchester,Birmingham,Blackpool and other midland /north west electrified routes to replace class 221's
class 805's to Chester,Holyhead,Wrexham,Shresbury and other unelectrified routes again replacing 221's