The who-was-Shakespeare industry is currently in full gear. “Last year saw no fewer than three hefty biographies, distilled from the slim documentary record of Shakespeare’s existence and coloured up into portraits through socio-historical detail and complex deductions from the plays and poems. Soon the Royal Shakespeare Company will launch a multinational season of the “Complete Works” at Stratford-upon-Avon, with 41 full-scale productions. And now we have the National Portrait Gallery’s Searching for Shakespeare, an exhibition centring on eight pictures that have at one time or another been accepted as true images of the Bard.”