Basically it needs rerouting, the days of business people using it are gone (cheap internal flights killed that).
They need to not think of it as a service between two city centres, but one serving leisure markets that are difficult to get to daytime. Not routes duplicating flights.
As an example, Midlands to Highlands, or Bristol to Lake District, or even Scotland to Southampton (splitting to coastal towns to Weymouth and Brighton)
Then change the marketing to journey as part of your holiday. It works for sleeper to Cornwall.