On Wed, 12 Mar 2014 22:55:26 +0000, Charles Ellson
wrote:

It can depend on which end of the round the postman starts at. When
one delivery a day came in it was evident in some places that the
round was being reversed every few weeks with the result that half the
round was getting the post earlier and the other half later. For some
time now (at least with mine) the delivery time seems to be mostly
unchanging.
The apparently delayed start time possibly also gets out of paying for
working unsocial hours.

Until about 5 years ago they were allowed to knock off early when they
finished their rounds. As a result many of them started well before
their official starting time.