15 day visa exemption - transfer time included?

Hi,

My wife and I are British passport holders and will be arriving in Hanoi on 28/2/17. We fly from Da Nang to Hanoi airport on 15/3/17 arriving at 21:35. However, our flight from Hanoi does not leave until 1:15am. Although this means we would be staying 1 hour and 15 mins over the 15 days (I am told arrival and departure days are included) would we still be eligible for exemption as that hour and 15 is spent in transfer, as we will not be leaving the airport?

Thanks in advance!