You already know which of your students are revising properly, and which are guessing.
Revision for T Levels barely exists. What is out there is written for A Level, or costs money, or both, and your students end up making it up as they go. T-SkiLL is built from the specification you teach, and every lesson is checked against that specification by students on the same course before anything is published.
Students join for free, on their own phones. It is built for revision at home, not for lesson time, so it asks nothing of your timetable.
The whole ask: tell your students it exists. They join themselves and start with your subject.