On the final day of her unofficial Australian tour, it was clear that Meghan, Duchess of Sussex, has replaced Catherine, Princess of Wales as a commercial fashion force. Expect sales of the blue and white striped $420 shirt from Australian label Matteau, worn by Meghan to Bondi and sailing on Sydney Harbour yesterday, to match those of the $389 khaki mini dress worn on Thursday from Melbourne label Friends With Frank , which (apart from one in an XL) sold out in 24 hours. After 10 outfit changes in four days – fewer than Margot Robbie on a movie press tour and four more than Princess Anne on her official four-day Australian visit in November – Meghan is the closest person to the crown who can drive sales for emerging labels. Meghan’s best looks: Day 4 Meghan in a Matteau striped shirt and Rolla’s jeans with Prince Harry at Bondi Beach. PA Images via Getty Images Gemma O’Neill with Meghan, Duchess of Sussex, wearing Scanlan Theodore, at the Her Best Life retreat in Coogee.…