I had an old plane a few weeks ago from Gold Coast to Sydney. The business class seat was the same size as an economy one and they just put a drinks thing in the middle seat.
Not quite the same size, it's actually a bit wider, the armrests on the middle seat move inward as the tray table is lowered. (The same concept as convertible J class seats on the QF 737-400 and Ansett 737s back in the day).