The two parts of your sentence contradict each other; a statement of fact must describe a past event (we moved our office) or current state (we cannot stay here due to Brexit). "We will move the staff" is a promise or a prediction, but it has not happened yet.
"I'm leaving the office at 5PM today" is a statement of fact, even though it hasn't happened yet.
"I've got a doctors appointment tomorrow morning" is a statement of fact, even though it hasn't happened yet.
That's not entirely True. "I intend to leave the office at 5PM today" is a statement of fact, it is neither True, or known to be True (epistemological the same) only once verified to some standard. You can assume "I intend" == "it will happen", but that's not a strongly accepted assumption.