Hi Kieran,
You can delete their responses to allow them to submit once more.
Do you allow responses to be seen by all students? If you are collecting student's info for staff use only, you can use Quiz or Lesson.
If you do want to work on Database, let me know, I can create it for you later.
But, use Feedback/Quiz/Lesson is much easier for your list of Yes/No question type.
Are you using the 'Checklist' plugin? It is good for the Yes/No checking as well, and it allows users to update their answer any time.
If you add Choice activities for each of your questions and set the Choice as 'Yes/No/Not sure', then, it will be easier for your teachers and students.