In what way would "Not Huddersfield", or "Chinley", or "Stockport/Romiley" not make sense? All would fit on the new format.
The one thing that does not make sense is having a ticket that has "Valid only via Stockport" printed on a ticket where that ticket is also valid via a route that does not pass through Stockport.
There is one thing, and one thing only that describes this - sheer laziness on the part of TPE (the fare setter).
1. Huddersfield does not lie on a mapped route between Liverpool and Sheffield, so 'Not Huddersfield' is a totally redundant route.
2. 'Via Chinley' is unsuitable because it could lead to tickets from Chinley being routed 'via Chinley' which is an oxymoron ans has been known to break things.
3. A route Stockport / Romiley is too long, so it would need to be illogically shortened down to fit into the route field on old tickets. This in itself may not present too much of a problem, but it would add to the maintenance of the data that's required. I notice that you haven't been leading any calls for 'Via High Wycombe' to be changed to 'Via High Wycombe / Little Kimble' even though that situation is exactly the same as this one.
The answer is to change the route to Any Permitted. There is no reason to do anything else. It's exceedingly unlikely though because while they can be very quick to
add new restrictions (including
without the proper authorisation to do so). The
removal of restrictions is rare. Furthermore it would go against the current industry agenda which states that 'Any Permitted' is too confusing. It seems they take the view that the current situation is "simpler".