Northern / Avanti question

[Tynedocker]

I intend to purchase a £12 Day Rover for Northern Trains. (Re newspaper offer)

I appreciate that under normal circumstances, it is not valid on Avanti trains.

However, due to the Cumbrian Coast route (operated by Northern) being subject to replacement
buses between Whitehaven and Corkickle, I note the following copied and pasted from the Northern website .....

.....Your ticket may also be used on Avanti West Coast services between Lancaster - Carlisle
(in both directions) If you require any connecting services, please check information screens,
visit www.nationalrail.co.uk/journey-planner/ or speak to a member of staff where available.

My question is, are the Northern £12 Day Rover tickets valid as well as standard every day tickets?