I posted these two images in another thread asking the question what is the X for.
In the photographs is a large Norfolk shoot peg selector with numbers one to ten plus an extra token with an "X". The full question was what time of the year was the selector used and what did the "X" signify. These Victorian shoot peg selectors are possibly not used a lot today because there are not that many very large estates in the UK now.

[Linked Image from i.imgur.com]

[Linked Image from i.imgur.com]

Possibly posting it here may have some results, Oh you wont find the answer in "Downton Abby" yes it is a Brit shooting Trivia question and I do know the answer.

The only lessons in my life I truly did learn from where the ones I paid for!