Interesting that GTR then claim that super off-peak London travelcards can't be put on the Key, considering the smart fares exist (and are used for keyGo). I wonder where the limitation is.Checking’s easy - pop to a TVM and try selecting a single/return onto a smartcard, noting the “Smart” prefix before every ticket. This becomes a bit more clear when looking at Brighton to Ashford Intl, where route ANY PERMITTED doesn’t have smart fares because it’s priced by Southeastern (the normal fares can just be fulfilled to ITSO), whilst route VIA EDENB/POLEG does have smart fares because it’s priced by Southern (GTR).