Update: Libera just posted on their Facebook page
"Look out for Libera on BBC-TV on Sunday 16th January when the boys will be singing 'Sanctissima' in a 'Songs of Praise' from Arundel Cathedral."
So it IS O Sanctissima! Will it be sung by Ben?
On January 16 at 5:00 p.m. the BBC One TV show Songs of Praise with have a feature on the town of Arundel. "Sally Magnusson discovers the historical secrets of the Sussex market town, and introduces hymns from the Roman Catholic Cathedral and a sparkling performance from Libera."
I wonder if this will be the Eternal Light video that they shot outside or something else filmed inside Arundel. dani on the Dreams forum said someone told her Libera filmed "O Sanctissima" in Arundel in October. Can't wait to find out! Thank you to treble53 from the French forum for finding this! And thank you dani! :)