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: TPO497
name: 20/1987
tree-preservation-order: undefined
20/1987
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.673294 51.272333,0.673426 51.272384,0.673527 51.272446,0.673740 51.272609,0.674183 51.272888,0.674458 51.273116,0.674679 51.273285,0.674811 51.273420,0.674971 51.273609,0.675032 51.273706,0.675071 51.273785,0.675087 51.273841,0.675106 51.273865,0.675107 51.273915,0.675076 51.273947,0.675024 51.273956,0.674929 51.273937,0.674684 51.273593,0.674613 51.273523,0.674464 51.273396,0.674257 51.273251,0.674158 51.273168,0.674081 51.273089,0.673643 51.272753,0.673487 51.272623,0.673180 51.272403,0.673174 51.272360,0.673230 51.272338,0.673294 51.272333)))
point: POINT (0.67425 51.273125)
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 - G16 comprising 3 Ash, 9 Oak,
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.