Ecosse eventually took over the Aston Martin sports car program before Leslie departed in 1990 to become part of Tom Walkinshaw's Jaguar team.

Leslie competed at the 24 Hours of Le Mans a total of 10 times, including driving the works Jaguar XJ220 in 1993 alongside Win Percy and Armin Hahne, only to retire with engine failure while in contention for the lead of the GT class.

For the BTCC in 1997 James Thompson and Gabriele Tarquini raced the Hondas and Leslie switched to Nissan alongside Anthony Reid.

He competed at the Spa 24 Hours that same year, sharing a Honda Accord with James Kaye and Mark Lemmer, but retired with engine failure.

He contested the Speedvision Challenge in the US during 2001 in addition to another outing in the British GT Championship (Knockhill), once again in a Marcos and finishing on the class podium.

He was flying with fellow racing driver and team owner Richard Lloyd and data engineer Chris Allarton.

[6] The investigation into the crash found that a combination of incorrectly identified, non-critical system failures led to the in-flight shut-down of both engines, with the crew unable to restart them in time to avoid the impact.