Playing devils advocate here regarding the Swiss Cottage.
There is no legal obligation to keep a grade 2 listed building in good shape. But owners are encouraged too. Local authorities can and do intervene if they believe the state of a building is at risk of deteriorating. The most extreme end of that spectrum being an urgent repair notice being served.
So basically there is an unwritten obligation to maintain grade 2 listed structures, but it is down to the discretion of the local authorities. Given the nature of Alton Towers, I would imagine they would want this building preserved, something this planning application seems to show it doing.
But, it only lists repair and making good work. Grade 2 listed status applies to the inside too, if they were planning on using it for something, I am sure they would need planning permissions of some sort for the inside, of which there is none. Fairly substantial work would need to be carried out inside too for it to be used for anything, as it is in a bad state, this would need planning permission. This says to me, the repair work being carried out is just that. Repair work. Work to keep the structure from detonating even further.
I could be wrong and I hope I am, I would love to see something there. But there is nothing in the application that supports this, and it would need to be in their due to its listed status.