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: TPO505
name: 6/1983
tree-preservation-order: undefined
6/1983
tree-preservation-zone-type: woodland
geometry: MULTIPOLYGON (((0.612562 51.276791,0.612570 51.276772,0.612559 51.276734,0.612645 51.276714,0.612657 51.276683,0.613300 51.276465,0.613830 51.276302,0.614175 51.276718,0.614573 51.277159,0.615047 51.277664,0.613527 51.278163,0.613442 51.278014,0.612972 51.277402,0.612755 51.277089,0.612600 51.276909,0.612580 51.276908,0.612491 51.276821,0.612520 51.276803,0.612562 51.276791)))
point: POINT (0.61373 51.277231)
notes: Maidstone Borough Council Tree Preservation Order No 6 of 1983 as varied by the Maidstone Borough Council Tree Preservation Order No.18 of 1988 made under Section 60 of the Town and Country Planning Act 1971
organisation
entry-date: 1988-11-05
start-date: 1988-10-14
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.