Simon Boccanegra, originally of 1857 but revised in 1881, has not traditionally been seen as Verdi’s greatest creation. When, however, in 2010 Plácido Domingo took on the title role, his first as a baritone, at the Royal Opera House in Elijah Moshinsky’s 1991 production, it injected a new level of interest into the piece. English National Opera got in on the act with a ‘film noir’ production in 2011, while Moshinsky’s version enjoyed a further revival...