In most cases we’ll do all we can to make sure latecomers can still enjoy the show.
We may hold latecomers in the foyer for a short amount of time, before seating at an appropriate moment (including the interval) to minimise disruption to both performers and other audience members. To avoid disruption, you may be asked to sit in alternative seats until the interval, when you can then move to your seats.
Some shows specify no latecomers, under any circumstances (mostly comedy). This will be clear online and on the ticket.