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: TPO399
name: 20/1987
tree-preservation-order: undefined
20/1987
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.664616 51.274543,0.664684 51.274571,0.665153 51.274885,0.665370 51.274998,0.665647 51.275170,0.666347 51.275642,0.667539 51.276370,0.667641 51.276444,0.667691 51.276514,0.667798 51.276561,0.667798 51.276598,0.667611 51.276660,0.667454 51.276532,0.666784 51.276093,0.666477 51.275922,0.666168 51.275712,0.665890 51.275513,0.665873 51.275492,0.665649 51.275339,0.665176 51.275065,0.664980 51.274935,0.664515 51.274703,0.664616 51.274543)))
point: POINT (0.666189 51.275624)
notes: The Maidstone Borough Council Tree Preservation Order No 20 of 1987 under Section 60 of the Town and Country Planning Act 1971 Group of Trees - G30 comprising of 36 Field Maple,
organisation
entry-date: 1987-07-14
start-date: 1987-07-09
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.