Here are a couple of the most popular videos from recent polyphonic Masses in Oxford sung by the Schola Abelis. If you like them, here are more; please consider making the Schola, the Oxford University Gregorian Chant Society, a donation.
If you are not getting to these, and could, you should make the effort! The next Masses of the Schola Abelis are on their Term Card.
At the Mass for the feast of St George we had a polyphonic Regina Caeli. This setting of the Regina Caeli is by Robert White (c. 1538 – 1574), an English Catholic composer.
At the Mass for the Pilgrimage to Littlemore, we had a Mass by Brumel. Here is the Chant Offertory (Exsultavit, for the Immaculate Heart of Mary) followed by a polyphonic motet, Brumel's Sub tuum praesidium.