The acclaimed Belfast artist Colin Davidson, noted for his portraits of Angela Merkel and Queen Elizabeth, has become embroiled in a legal wrangle with one of Dublin’s best-known art dealers. Davidson, who has also painted Ed Sheeran and Brad Pitt, is suing the Oliver Sears Gallery, and Sears personally, looking for a substantial number of his artworks to be returned. The 51-year-old also wants to sever ties with the gallery, which has a highly regarded stable of contemporary artists including Hughie O’Donoghue, Michael Canning and the late Barrie Cooke. High Court proceedings were issued yesterday against the Gallery and London-born…