The second of Nick Baker’s three-part investigation proved once again that a radio programme’s merits may exist in inverse proportion to the account of it given in the Radio Times. In a decade’s worth of reviewing, one of the dullest-sounding – and also one of the most absorbing – items I ever chanced upon was a feature about the members of a tape-recording club in 1960s Derby. If Exit Through the Gift Shop (19 March) didn’t quite scale these Olympian heights, then it was a fail-safe demonstration of what can be achieved by putting a microphone in front of half-a-dozen ordinary people and letting them talk.Variously at large in the gift shops of the Museum of Scotland, Tate Liverpool, the Museum of Liverpool and the Victoria and Albert Museum, Baker too