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: TPO716
name: 18/1986
tree-preservation-order: undefined
18/1986
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.636829 51.294631,0.636925 51.294643,0.637084 51.294721,0.637114 51.294788,0.637112 51.294850,0.637038 51.294886,0.636874 51.294918,0.636784 51.294963,0.636657 51.294974,0.636516 51.294939,0.636389 51.294872,0.636322 51.294811,0.636281 51.294757,0.636292 51.294701,0.636335 51.294663,0.636487 51.294661,0.636599 51.294673,0.636665 51.294650,0.636829 51.294631)))
point: POINT (0.636703 51.294792)
notes: The Maidstone Borough Council Tree Preservation Order No 18 of 1986 under Section 60 of the Town and Country Planning Act 1971 Group of Trees - G13 - 8 Oak, 1 Ash, 1 Field Maple
organisation
entry-date: 1986-08-13
start-date: 1986-07-19
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.