A reader: "Mr. Derbyshire—-Regarding the pun you quoted, I understand Lord Montague when caught in a compromising situation after promising to turn over a new leaf, was quoted as saying: 'I have to get to the bottom of this page first.'"
New leaf... page... got it.
Lord Montague of Beaulieu (pronounced "Bewley") features in a number of stories in this general zone. Also at least one song: Anyone who has been bused to an away rugby game will recall the spoof of "The Twelve Days of Christmas" whose refrain ends: "...And My Lord Montague of Beaulieu." The other Christmas gifts in that spoof have... escaped my memory.