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: TPO836
name: 15/1986
tree-preservation-order: undefined
15/1986
tree-preservation-zone-type: area
geometry: MULTIPOLYGON (((0.661914 51.269353,0.661977 51.269356,0.662039 51.269375,0.662100 51.269408,0.662191 51.269492,0.662268 51.269585,0.662440 51.269843,0.662553 51.270035,0.662567 51.270096,0.662546 51.270132,0.662506 51.270142,0.662404 51.270137,0.662307 51.270106,0.662216 51.270048,0.662106 51.269961,0.662049 51.269900,0.661834 51.269742,0.661705 51.269596,0.661666 51.269509,0.661673 51.269475,0.661696 51.269433,0.661778 51.269375,0.661914 51.269353)))
point: POINT (0.662113 51.269725)
notes: Maidstone Borough Council Tree Preservation Order No 15, 1986 under Section 60 of the Town and Country Planning Act 1971 dated 18th July 1986. Confirmed 8th October 1986
organisation
entry-date: 1986-08-13
start-date: 1986-10-08
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.