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: TPO221
name: 21/1987
tree-preservation-order: undefined
21/1987
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.659056 51.275673,0.659119 51.275679,0.659237 51.275728,0.659280 51.275765,0.659339 51.275839,0.659357 51.275886,0.659384 51.276008,0.659385 51.276099,0.659364 51.276130,0.659337 51.276151,0.659294 51.276164,0.659208 51.276153,0.659073 51.276082,0.659015 51.276041,0.658939 51.275972,0.658824 51.275852,0.658805 51.275811,0.658805 51.275770,0.658826 51.275737,0.658889 51.275705,0.658979 51.275680,0.659056 51.275673)))
point: POINT (0.659122 51.275901)
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 - G16 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.