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: TPO620
name: 1/1975
tree-preservation-order: undefined
1/1975
tree-preservation-zone-type: area
geometry: MULTIPOLYGON (((0.597291 51.292237,0.597190 51.292046,0.596853 51.291643,0.596769 51.291553,0.596707 51.291465,0.596688 51.291424,0.596685 51.291387,0.596681 51.291186,0.596664 51.291056,0.596668 51.290959,0.597011 51.290881,0.597195 51.290857,0.597291 51.290831,0.598623 51.290598,0.598903 51.290514,0.599180 51.290392,0.599387 51.290320,0.599377 51.290437,0.599333 51.290464,0.599207 51.290510,0.598974 51.290614,0.598743 51.290689,0.598577 51.290726,0.598436 51.290723,0.598282 51.290762,0.598113 51.290777,0.597532 51.290856,0.596794 51.291002,0.596758 51.291045,0.596748 51.291083,0.596758 51.291158,0.596788 51.291237,0.596819 51.291392,0.596880 51.291528,0.596964 51.291652,0.597051 51.291756,0.597162 51.291910,0.597289 51.292064,0.597398 51.292171,0.597291 51.292237)))
point: POINT (0.597781 51.291001)
notes: County of Kent (Maidstone Borough) Tree Peservation Order No. 1 of 1975 under Section 60 of the Town and Country Planning Act 1971. Area of Trees - A2 the seceral Oak, Buckthorn, Field
organisation
entry-date: 1975-10-29
start-date: 1975-09-30
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.