With his wife Rosemary Squire he ran the Ambassador Theatre Group from about 1995 until 2016; they remain directors and shareholders of the company.

[2][3] In a guide to "the 100 most influential people in UK theatre" published by The Stage, Panter and Squire were placed first each year from 2010 to 2016.

[6][7] In 1991, with Sir Eddie Kulukundis and the brothers Peter and John Beckwith, Panter became a director of a company which bought the Duke of York's Theatre and in 1992 was renamed The Duke Of York's Theatre (Holdings) Limited.

[2][3][10][11] Panter is on the development board of LAMDA,[12] and was chairman of the Rambert Dance Company for ten years.

[24][25] Panter met Rosemary Squire at the Queen's Theatre in London, where both were working during his production of And a Nightingale Sang with Patricia Routledge.