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: TPO251
name: 20/1987
tree-preservation-order: undefined
20/1987
tree-preservation-zone-type: group
geometry: MULTIPOLYGON (((0.661574 51.281776,0.661621 51.281795,0.661652 51.281849,0.661642 51.282097,0.661660 51.282198,0.661663 51.282308,0.661611 51.282915,0.661562 51.283108,0.661544 51.283143,0.661508 51.283146,0.661475 51.283138,0.661448 51.283117,0.661444 51.283042,0.661466 51.283002,0.661478 51.282886,0.661469 51.282811,0.661518 51.282344,0.661513 51.282041,0.661547 51.281788,0.661574 51.281776)))
point: POINT (0.661565 51.282476)
notes: The Maidstone Borough Council Tree Preservation Order No 20 of 1987 under Section 60 of the Town and Country Planning Act 1971 Group of Trees - G22 comprising of 1 Grand Fir,
organisation
entry-date: 1987-07-14
start-date: 1987-07-09
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.