Excellent and unusual Flip. One that would be a good accompaniment to a nod by the tree on Christmas Eve.
An interesting historical note: this drink was created the year after the only other (classic) drink I know that contains both Chartreuse and Benedictine: the Widow's Kiss. Can't help but wonder if it was inspired by the recent creation of that most "evocative" concoction.
Dear Simon, and/or team. I thought you might like to know that this recipe appears in print earlier than 1903. It's on page 40 of the 1896 book "Drinks of all kinds" by Frederick Davies and Seymour Davies.