Use Royal Mail
Not a conspiracy theory or anything but a little birdy has informed me that at a busy business orientated airport in Hants, a lot of postal votes for the Pension Ballot were placed in the NATS external Mail slot.
It was unfortunate for the substantial number of voters at that unit that it was not until after the ballot closed that it was discovered the mail had not been sent resulting in a large number of votes not being counted (allegedly a high proportion of 'NO' votes - not enough to change the result mind).
Use Royal Mail!!!