Would you drive with exhaust filter light on?

[tight fart]

My daughter has called for advice, the Red warning light has come on on her 3 year old Discovery sport.
She never got an amber warning first.
She called the AA, they said don’t drive it contact the main dealer.
He had connected a diagnostic computer and said there was a valve open that shouldn’t be.
Land Rover can’t do anything for a week.
The car has had some 70 mile runs in the last week so not just stop start journeys.
If it were mine I’d run it up the motorway and hold it in a low gear but the experts are saying don’t.
Any thoughts?

[tight fart]

Out of warranty, an indi has charged her £360 for a “computer generated re-
and it’s up and running again. At least it kept dad out of the firing line.