David Cantrell gurgled happily, sounding much like
they were saying:

I thought the whole point of postcodes was to carve up the country
based on the most efficient way to organise deliveries. In which case,
why aren't postcodes also better for other businesses

Errm, because other businesses aren't in the business of organising
postal deliveries but instead of doing things like selling houses or
offering plumbing services. In those cases, what matters are that the
customers live (for example) in Hastings, not that they have a TNxx xxx
postcode.

Or, quite simply, that other delivery businesses might not have their
depots in the same layout as RM.