Instead of a corporate letterhead, they require the wax seal of the eldest son of the Family von Baron MCMLXIV, Viscount of Parcelforce, Duke Du Jour, and Most

Instead of a corporate letterhead, they require the wax seal of the eldest son of the Family von Baron MCMLXIV, Viscount of Parcelforce, Duke Du Jour, and Most Charitable and Venerated Grand Master of Her Majesty's Royal Letter-Stampers (or his designated representative), which is then simply cross-checked against Burke's for validity. Time-tested and infallible - even more-so than the Pope, if it can be believed.