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: TPO911
name: 9/1975
tree-preservation-order: undefined
9/1975
tree-preservation-zone-type: woodland
geometry: MULTIPOLYGON (((0.562736 51.261027,0.562735 51.261076,0.562706 51.261131,0.562657 51.261173,0.562581 51.261216,0.562492 51.261254,0.562255 51.261327,0.561933 51.261453,0.561890 51.261452,0.561842 51.261480,0.561842 51.261494,0.561740 51.261542,0.561492 51.261619,0.560919 51.261749,0.560018 51.261921,0.559914 51.261927,0.559834 51.261914,0.559801 51.261894,0.559759 51.261827,0.559840 51.261416,0.559850 51.261404,0.559950 51.261397,0.559946 51.261444,0.559952 51.261465,0.559997 51.261550,0.560059 51.261611,0.560094 51.261634,0.560153 51.261655,0.560225 51.261674,0.560383 51.261689,0.560490 51.261687,0.560624 51.261671,0.560764 51.261651,0.560991 51.261588,0.561130 51.261538,0.561234 51.261486,0.561270 51.261428,0.561445 51.261386,0.561508 51.261331,0.561525 51.261326,0.561553 51.261297,0.561571 51.261290,0.561601 51.261281,0.561622 51.261286,0.561674 51.261324,0.562017 51.261301,0.562558 51.261099,0.562735 51.261021,0.562736 51.261027)))
point: POINT (0.561022 51.261564)
notes: Maidstone Borough Council Tree Preservation Order No. 9 of 1975 under Section 60 of the Town and Country Planning Act 1971. Woodlands - W2 Comprising Willow (Salix species)
organisation
entry-date: 1975-02-26
start-date: 1975-02-20
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.