Creating the right impression starts with envelope choice. For smaller business/sales mailings you may want to put the name and address on a non-window envelope to make it look more personal and to include a personalised letter.
Recent UK pillar boxes have the initials ERII (Elizabeth Regina II), while older ones are inscribed with GVIR, GVR, and more, with some going as far back as to have VR on them (for Queen Victoria). Instead, Scottish post boxes have the Scottish crown, the words “post office”, or some combination of the two.
From 1927 to 2003, Royal Mail in London had its own Underground rail system, dubbed “Mail Rail”. The line ran from the Paddington Head Sorting Office to the Eastern Head District Sorting Office in Whitechapel. It operated 19 hours per day for 286 days per year and carried around 4 million letters a day.