It may have changed (drinks). But a little tip.
The boxes were attended by a drinks wait team, who were pleased for one’s regular box drinks orders. Have a discreet word, plus an appreciation, for the “reservation” of a particular box on non-Gala nights, then there should will be no need for a vary early pre-show rush and grab. Up stairway, along floor, no space, back, up, repeat. On these evenings boxes appeared to be popular with those wishing not to follow the published dress code, entering the Theatre box unobserved via the deck 1 “rat runs”.
The stairways to the entrances of boxes, on multiple levels, are a tad steep and narrowish, so people with mobility issues should be aware.