“If the tale of Rosemary Squire and Sir Howard Panter, the husband and wife team who built a theatrical empire from scratch, was ever turned into a play (and it would make a mighty fine one), then the first act’s set would centre round a little red BMW. Twenty-five years ago, … backstage space was tight and there was no cash left to rent an office. So Squire parked outside the theatre and – with one eye open for zealous traffic wardens – tackled her paperwork from the driver’s seat.”