There was mail from the Royal Mail in Great Britain for me todayβ with South African stamps inside, of course.
I looked up the details of the stamps used on the envelopes.

Issued 1974, Oct. 9. | Perf.14Γ15 | βAll-overβ phosphor Gum
962 444 4Β½p | Prussian Blue, pale turqoise-green and silver | Churchill in Royal Yacht Squadron Uniform
[Source: 1997 Stanley Gibbons Stamp Catalogue Part I Volume I]

Issued 2023 | Perf. 15Γ14Β½ | Gravure print with phosphor bars | Bar-coded | Self-adhesive
Β£2.20 Dark green Portrait of His Majesty King Charles III
[Source: royalmail.com]