The Bluetooth thing is WAY more useful for turning the vac from the hose end than it is for the "Festool cordless" use case.
In your case, I would go for the Mini instead. But this is European view where the price diff is a bit less.
Again, price diff aside, the CT15 is really good for static single-tool use. Once you consider it as a general vac, it becomes just too compromised.
That said, per eKat, the hose garage set is part # 204717. Most retailers will not stock it explicitly but it can be ordered as a spare part.
Though a better way may be to sell your "semi-garage" to a Mini owner who wants to reduce the footprint of his vac ...