Gemma Farrell, an investment manager at Duke Street, the private equity group, which recently acquired Wagamama, has joined the fast-casual noodle chain, as a non-executive director. Farrell, who has been with Duke Street since September 2010, is also a non-executive director of Sandpiper CI, the Channel Islands-based retail group. Last month, Duke Street, which acquired the noodle chain from Lion Capital for around £215m, announced plans to expand Wagamama to 300 UK restaurants. It opened its latest site in England, in Horsham in May, taking its UK estate to 72 restaurants. The chain is set to open its first restaurant in Edinburgh later this summer, after securing a former Bank of Scotland site in the city.