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: TPO203
name: 21/1987
tree-preservation-order: undefined
21/1987
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.664732 51.272174,0.664776 51.272176,0.664866 51.272206,0.665048 51.272328,0.665169 51.272431,0.665704 51.272844,0.665864 51.272956,0.666288 51.273332,0.666372 51.273430,0.666401 51.273476,0.666385 51.273511,0.666363 51.273535,0.666339 51.273545,0.666177 51.273579,0.666049 51.273571,0.665977 51.273531,0.665781 51.273347,0.665649 51.273240,0.665236 51.272868,0.665000 51.272646,0.664712 51.272306,0.664694 51.272242,0.664694 51.272213,0.664732 51.272174)))
point: POINT (0.665567 51.272938)
notes: The Maidstone Borough Council Tree Preservation Order No 21 of 1987 under Section 60 of the Town and Country Planning Act 1971 Group of Trees - G2 comprising
organisation
entry-date: 1987-07-31
start-date: 1987-07-30
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.