If I tell you that on Monday there was an hour-long documentary about the history of stamp-collecting, then you probably don’t need this column’s usual bit in brackets saying which channel it was on. Indeed, at times Timeshift: Penny Blacks and Twopenny Blues seemed determined to be the most BBC4-like programme in the history of BBC4: cheerfully niche, heroically indifferent to all notions of cool and so old-school in its production style that any mention of France was introduced with a blast of accordion music.