RailForums is blocked on TPE WiFi, so I can belive that this would be an intentional block with some TOCs.Ironically blocked by Loop WiFi on LNWR. Have tried to report it to Open DNS as an incorrect block, but it's not happening.
The website is also available via https://storage.googleapis.com/faremap.ml/index.html#Ironically blocked by Loop WiFi on LNWR. Have tried to report it to Open DNS as an incorrect block, but it's not happening.
You will struggle. The problem is the bonkers cheap fare between Gatwick and East Croydon.I struggle to find any Oyster fare to Gatwick that is not cheaper if splitting at East Croydon or somewhere around there in zone 6, like Purley. I imagine the fares within zone 2-6 are subsidised a lot more than those beyond.