I downloaded it via the BBC iPlayer. Normally the downloads self-destruct after a month, I believe... but there are ways and means to keep them

"Timeshift" is appropriate in the case of this documentary. It could have been done in the 1950's with the posh-voiced reporter, the "Oh, a woman collector but it's ok as she collects cat stamps", the age-ist "nobody under 55 in the room" attitudes. It tells you very little about the actual stamps in the title.
BBC at its worst and so, so different from the stunning EARTH 2 series with David Attenborough (no stamps were injured in the making of his series).