There have been threads before about this where the consensus was that ITSO enabled TVMs are rare in the Oyster area, some exceptions being London St Pancras, London Marylebone and a few others.
It seems this information is recorded in nationalrail.co.uk under "Stations". If you look up a station and then click on "Ticket buying and collection" a popup will appear showing what Oyster and smartcard facilities are available. It correctly shows ITSO enabled TVMs at St Pancras and Marylebone ("Load smartcard at ticket machine") so I tried a few other stations I know reasonably well.
It claims you can also load smartcards at ticket machine at both London Waterloo and Clapham Junction but I've never noticed any ITSO enabled TVMs at either. Then I tried Reigate - not in the Oyster area admittedly, but the system incorrectly says no smartcard tickets can be purchased. This is definitely wrong as I recently purchased one there from the TVM.
It seems this information is recorded in nationalrail.co.uk under "Stations". If you look up a station and then click on "Ticket buying and collection" a popup will appear showing what Oyster and smartcard facilities are available. It correctly shows ITSO enabled TVMs at St Pancras and Marylebone ("Load smartcard at ticket machine") so I tried a few other stations I know reasonably well.
It claims you can also load smartcards at ticket machine at both London Waterloo and Clapham Junction but I've never noticed any ITSO enabled TVMs at either. Then I tried Reigate - not in the Oyster area admittedly, but the system incorrectly says no smartcard tickets can be purchased. This is definitely wrong as I recently purchased one there from the TVM.