score:3
You can use the Velocity Frequent Flyer (Virgin Australia's loyalty program) Status Earn Fare Class table to perform the conversion - https://www.velocityfrequentflyer.com/content/Info/StatusEarnFareClass/
In that table, you can see that T
falls under Discount Economy which is the other name for Saver/Saver Lite. The table does not differentiate between Saver and Saver Lite as the difference is just that one includes checked luggage, and the other does not. Full Fare Economy means Flexi. Business means Business.
If you want to see what booking class the fare is when booking on the Virgin Australia site, simply select your flights, then on the right side just under the total cost, click View Fare Rules. In the popup, you'll see a tab for each flight chosen. Underneath the tab, you'll see a line that starts with Fare Basis, e.g.
Fare Basis: TSALE
The first letter of the fare basis is the booking class.