The desk
Write with a question, not a brief in full
Name the market, the years, and the decision the charts must serve. A complete dossier is not required on the first letter.
The desk reads incoming notes within two working days. If a first sitting is possible, we usually offer a date inside a fortnight. Telephone if a board date is already fixed and the post would be too slow.
Walk-ins are not a substitute for a source list. If you are nearby, you may leave papers at Level 10; say so in the note so someone is at the table.