There is a rule that ‘vote follows voice’. This means that your call of “Aye” or “No” should match your vote in the division. For example, if you call “No” when the question is put, you shouldn’t then vote Aye in the division.
You may change your original call when the Speaker puts the question a second time. There is no obligation to vote if you’ve called one way but don’t want to record your vote in the division.
Any objection that an MP has voted the opposite way from the way they called should be made before the numbers are reported by the tellers if possible or, if not, immediately afterwards.