Tree preservation zone

There is a problem

1000 entries with tree-preservation-order field must match the reference field in the tree preservation order dataset

reference: TPO950
name: 7/1990
tree-preservation-order: undefined
7/1990
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.661579 51.252958,0.661870 51.252906,0.662098 51.252877,0.663006 51.252817,0.664033 51.252848,0.664614 51.252848,0.664949 51.252857,0.665436 51.252894,0.665781 51.252911,0.665866 51.252924,0.665952 51.252954,0.665961 51.252967,0.665949 51.252989,0.665839 51.253013,0.665721 51.252999,0.665002 51.252954,0.664518 51.252962,0.663667 51.252950,0.662796 51.252949,0.661779 51.252988,0.661699 51.252999,0.661626 51.252994,0.661579 51.252958)))
point: POINT (0.663756 51.25291)
notes: The Maidstone Borough Council Tree Preservation Order No 7 of 1990 under Section 60 of the Town and Country Planning Act 1971 Group of Trees - G24 consisting of 29 Ash,
organisation
entry-date: 1990-10-05
start-date: 1990-10-02
end-date

Your dataset is missing the tree-preservation-order column.

The Tree preservation zone guidance explains how to fix the issue:

The reference for the tree preservation order that covers this zone.