To reset the app:
- Start the app
- Tap "THEORY TEST"
- Tap "Progress Monitor"
- Tap "Reset Scores", "Reset all progress" and (if prompted) confirm
- Tap "<-" (top left)
- TAP "HAZARD PERCEPTION"
- Tap "Settings" (the cog icon)
- Tap "RESET PRACTISE SCORES" and confirm
- TAP "RESET MOCK TEST SCORES" and confirm
- Tap "<-" (top left)
If the app isn't immediately reset, power the device device off and back on (not just to sleep - Apple see here).