Maybe I am being very slow - but how can you find the underlying fare code you are ticketed on? When you login to the VS website and look at your trip details, it just lists the cabin you are flying in. We all know the difference in cost between the cheapest non-flexible fare & full fare in the same cabin can be eye-watering.
The website never has shown the fare code. It's only displayed in the app under where is says 'Show Passenger' then 'View'.
The other option is to view your booking confirmation email.