While Slater has dominated Ginetta Junior this season, Clarke has been the undisputed star of the Clubmans Sports Prototype category and scored another two triumphs in his Phantom PR22 at Oulton Park, his lead almost 40 seconds each time.
Not only do those successes narrow the gap to Slater, but they also propel Clarke back to second a week after dropping behind Lucas Romanek.
It was a rare weekend without Romanek being in Formula Ford 1600 action and McLeish relegated him another place as he also picked up two wins.
Having enjoyed plenty of glory in the Scottish Legends series, McLeish entered his local round of the British Touring Car-supporting Elite Cup contest at Knockhill and continued his strong form. He also moves up one spot on the leaderboard.
Behind Romanek, in fifth place is another driver to move up one place as Aidan Hills achieved a Mazda MX-5 Supercup win at Cadwell Park. But it was just the one victory this time for Hills, who was narrowly defeated in the opener.
Another MX-5 conqueror was Steve Foden, who twice topped the Mk1 championship to jump two places into sixth.
Source: Autosport