This brown bear chamber group is classically trained. They hail from the same part of England as my great-great-grandparents: Burnley in Lancashire. I really don’t think there is a tambourine part in this particular Bach motet that they are singing, but Barley is a tambourine virtuoso and it would be a shame not to use his skills.
As an aside, several years ago I took a week long summer seminar for band directors. One day our percussion teacher said that the whole class time the next day would be devoted to tambourine technique. I was a vocal major turned band director, so I raised my hand and asked “What is it that I don’t know about tambourine that we could possibly talk about for a whole hour?”. Well, the teacher was not amused and everyone else just stared at me. Apparently, there WAS a whole lot I didn’t know!