The deadline is rapidly approaching. But Duncan Campbell, one of the three artists chosen to represent Scotland at this year’s Venice Biennale, is still, when we meet, not quite sure what he will present to the world this June. The Irish Glasgow-based artist, along with fellow artists Corin Sworn and Hayley Tompkins, will show his art at the 15th-century Palazzo Pisani next month as the official display of Scotland + Venice.