In 1998 however he made rapid progress as he took a minor event at Haydock Park before winning the Chester Stakes and then recording his biggest success in the Group 1 Prix du Cadran.
A member of the Wills family of tobacco merchants Sir David established the Ditchley Foundation and was described as "one of the greatest but least-known benefactors of the post-war era".
Ridden by Michael Hills he recorded his first success as he took the lead three furlongs out and prevailed in a tight finish by a head from the Henry Cecil-trained favourite Awesome Wells.
He produced a better effort when finishing runner-up at Doncaster in June and then started odds-on favourite when carrying 140 pounds in a minor handicap over fourteen furlongs at Haydock on 3 July.
Invermark pulled clear in the closing stages to win by 3+1⁄2 lengths from the filly Delilah (Princess Royal Stakes) with the favourite Perfect Paradigm (Old Newton Cup) in third.
Ridden by the locally based Olivier Peslier he led for most of the way before being overtaken in the closing stages and finishing fourth behind Tiraaz, Solo Mio and Asolo, beaten two lengths by the winner.
Ridden by Hughes he raced towards the rear before producing a strong late run and taking second place behind Enzeli in a field which also included Kayf Tara, Celeric, Nedawi and Persian Punch.
In the Prix Kergorlay at Deauville Racecourse in August he stayed on well in the straight but proved no match for Kayf Tara and was beaten five lengths into second place.
[13] On his only other appearance of the year he started 2/1 favourite for the Jockey Club Cup at Newmarket on 20 October and finished a close second to the three-year-old Capal Garmon, with Royal Rebel and San Sebastian in third and fourth.
On his final racecourse appearance the gelding ran for the second time in the Ascot Gold Cup and came home seventh of the fifteen runners behind Royal Rebel.