Richard J. wrote:

The moral of all this - an a moral all too frequently not understood by
the Great British Public - is that postal addresses and administrative
geography un Britain are very different things.

The bigger problem is not that it's poorly understood by the public, but
that it's poorly understood by businesses who attempt to carve up their
service areas based on postcode, when administrative (and physical)
geography is usually a better idea.

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, rather than
administrative geography which is often still based around historical
boundaries that have little relevance today?

Well it was actually the most efficient way in the past although the post
codes could have some extreme versions and in general reflect the way mail
was actually moved around at the time - the most extreme I can think of was
the PA postcode which once reached all the way up to the Butt of Lewis
because mail to the Outer Hebrides went via Abbotsinch airport. I wouldn't
be surprised if other post codes reflect the use of rail at the time and
don't bear the best relation for how other companies deliver services - e.g.
insurance where premiums vary quite a lot on either side of the London post
code boundary for no reason other than that.