The Cheveley Park Stud-owned filly completed a double on the day for the team following Princess Loulou's win at Doncaster.
It was a straightforward victory for Mediation who had good form in the book having been placed at Newbury and Ascot on her two previous starts.
She sat second of the four runners under Jack Mitchell with the leader Alhania going off at a decent tempo.
The leader soon paid the price for her early excusions and Mediation was left in front on turning for home.
She soon strided clear of her rivals to record an easy four-length win.
Roger said: "Mediation is a well-bred filly who has shaped well on both her previous starts. She has done it nicely."