_{This puzzle is a part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted reply to this query can be awarded a bounty price 50 popularity.}

< Previous Door

“Good night, Chief Inspector. Pat Terne once more?”

“Yes. We ought to have been on this one a very long time in the past, however the Royal Mail simply handed over the proof this afternoon.”

“The Royal Mail?”

“It’s diabolical, Sequence…there is not any different phrase for it. Terne compromised one of many employees who handles the letters to Father Christmas.”

“That soiled…”

“I do know, Sequence. But we’re going to want a Christmas miracle to crack this code. I hate how Terne telegraphs his strikes, however we nonetheless hold lacking him!”

“What do we now have?”

“Eight letters to Father Christmas. We solely discovered them as a result of the confederate was on vacation when the final one got here in. A vacation he by no means got here again from.”

“How was the final one detected?”

“It arrived within the workplace on July 4. It’s fairly uncommon to obtain letters to Father Christmas midway by means of the yr.”

“Technically it is a bit greater than midway. July 4th was the 185th day of the…”

“Moving on…on high of that, it was from Turkey.”

“And the others?”

“Found within the confederate’s desk, together with a notepad of scribbled sequences of numbers, principally scratched out.”

“What have been the contents?”

“Nothing. Zip. Nil. The envelopes have been all empty, even the final one we acquired. Just eight envelopes.”

“Well, let me see the envelopes.”

Sgt. Sequence regarded over the envelopes for a couple of minutes, then returned to his desk and after a couple of minutes of looking out the Internet, he returned.

“It’s Terne alright sir, and this can be one in all his boldest capers but. Cancel the workforce’s holidays…we’ll be busy foiling a theft.”

Based on the envelopes beneath that Sgt. Sequence inspected, can you identify the place and when Terne plans to strike?

Solver Notes

The letters beneath or sorted alphabetically by origin nation. This might or might not be vital to the puzzle answer. Many because of Stiv for once more permitting me to borrow his characters!