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: TPO617
name: 15/1976
tree-preservation-order: undefined
15/1976
tree-preservation-zone-type: woodland
geometry: MULTIPOLYGON (((0.614444 51.290311,0.614467 51.290161,0.614139 51.289690,0.613890 51.289629,0.613880 51.289621,0.613922 51.289468,0.614028 51.289240,0.614068 51.289184,0.614115 51.289141,0.614168 51.289097,0.614202 51.289085,0.614266 51.289076,0.614314 51.289081,0.614429 51.289125,0.614461 51.289153,0.614476 51.289183,0.614465 51.289225,0.614457 51.289393,0.614551 51.289459,0.614851 51.289519,0.615235 51.289497,0.615300 51.289499,0.615319 51.289507,0.615350 51.289548,0.615410 51.289670,0.615391 51.289802,0.615404 51.289982,0.615401 51.290054,0.615418 51.290070,0.615449 51.290078,0.615538 51.290076,0.615568 51.290067,0.615602 51.290079,0.615607 51.290102,0.615572 51.290212,0.615548 51.290238,0.615483 51.290221,0.615412 51.290230,0.615347 51.290226,0.615080 51.290273,0.614783 51.290312,0.614542 51.290295,0.614444 51.290311)))
point: POINT (0.614715 51.289773)
notes: Maidstone Borough Council Tree Preservation Order No. 15 of 1976 under Section 60 of the Town and Country Planning Act 1971. Woodlands - W1 Comprising a mixed woodlad
organisation
entry-date: 1976-07-12
start-date: 1976-07-02
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.