His record includes the Tourist Trophy at Dundrod and the 24 Hours of Le Mans (although his co-driver Mike Sparken retired before Gregory got a chance to drive).
O seu rexistro inclúe o Trofeo Turístico da RAC en Dundrod e as 24 Horas de Le Mans (aínda que o seu co-piloto Mike Sparken retirouse antes de que Gregory tivese a oportunidade de pilotar).