Stewart performed in the European premiere concert tour of CHESS, and in CRICKET by Tim Rice and Andrew Lloyd Webber for the Royal Family at Windsor Castle, and subsequently at the Sydmonton Festival. He was Music Associate for WHO COULD ASK FOR ANYTHING MORE?, the Ira Gershwin Centenary Concert at the Royal Albert Hall in 1996, and in 1998 conducted the George Gershwin Centenary Concert at the London Palladium. He conducted the OPENING GALA CONCERT and a concert version of ANYONE CAN WHISTLE as part of the inaugural International Festival of Musical Theatre in Cardiff in 2002.

He conducted the Welsh National Opera Orchestra in 'S WONDERFUL, a programme of Gershwin music at St David's Hall in Cardiff, and was Musical Director of the ROYAL GALA OPENING CONCERT at the new Wales Millennium Centre in Cardiff in 2004, where the programme included a variety of styles including pop, opera, swing and musical theatre; he was particularly delighted to have the opportunity to conduct for the Kirov Ballet. The following year he gave a masterclass on the songs of Cole Porter as part of the 2005 International Festival of Musical Theatre.

He conducted a choir which sang his own setting of ECCE SACERDOS MAGNUS for Pope John Paul II at an Audience in the Vatican; the choir also sang masses at St. Peter’s Basilica in Rome and at the Basilica of St. Francis in Assisi. Amongst a broad variety of other corporate work, he was commissioned to compose and conduct a choral work, PROSPER THOU THE WORK OF OUR HANDS, to celebrate the opening of the Queen Elizabeth II Bridge over the Thames at Dartford, which was performed for the Queen by a choir of over 600 voices, accompanied by the Band of the Royal Engineers.