With the Royal Opera entrenched as the country’s premium company, the ENO at the London Coliseum (1904) is the progressive one that angles for younger audiences. Tightening purse strings have made it slimmer and more crowd-pleasing; its 2016 revival of Glenn Close in Sunset Blvd. was a particular smash. The 11-show slate consists of both progressive choices and classics. Best of all, it sets aside 500 seats at every performance for £20 or less.