If you arrive late for the start of a performance or after an interval we appreciate that you will want to take your seat as soon as possible. We will do everything possible to assist. To limit disturbance to fellow audience members and artists we may have to ask you to wait until a suitable break in the performance.
We’ll help you take your seat as quickly as possible, but you might need to wait until there’s a break in the performance. That way, we won’t disturb the performers or other audience members.
Source: Box office and ticketing FAQ