In my experience of civil service office moves
These are now largely aimed fashionably as hot desking offices with no cupboards, phones or anything else.
As they move from "old fashioned" offices any documents, contracts, plans, boarding cards, manuals, or any other kind of paper record is destroyed 1) as there is nowhere to put them, 2) no planning or audit of what they are or if they are important and 3) digitising them comes at a cost to deliver and maintain that no department has a budget for...
So I am not surprised. I will not be surprised when this happens again and again either. It does not matter in government/civil service if records need to be kept, there are few ways of doing so, and fewer than will realistically be performed.