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: ZZZZZWESRW793
name: Bucks. County Council (Eton Rural District) Tree Preservation Order No.4; 1956; dated 22/3/56 under
tree-preservation-order: undefined
TPO/BCC/1956/04
tree-preservation-zone-type
geometry: MULTIPOLYGON (((-0.516694 51.546331,-0.516690 51.546335,-0.518315 51.546586,-0.518719 51.546647,-0.518773 51.546654,-0.518792 51.546651,-0.518805 51.546646,-0.518837 51.546614,-0.518855 51.546580,-0.518868 51.546477,-0.518888 51.546474,-0.518890 51.546432,-0.518888 51.546376,-0.518885 51.546352,-0.518884 51.546320,-0.518875 51.546260,-0.518863 51.546159,-0.518853 51.546100,-0.518829 51.545933,-0.518759 51.545541,-0.518707 51.545218,-0.518709 51.545204,-0.518796 51.545141,-0.518921 51.545046,-0.519073 51.544935,-0.519161 51.544869,-0.519183 51.544850,-0.519643 51.544413,-0.519804 51.544255,-0.520254 51.544138,-0.520711 51.544016,-0.520609 51.543794,-0.520587 51.543750,-0.520386 51.543367,-0.520358 51.543336,-0.520311 51.543293,-0.520277 51.543276,-0.520179 51.543358,-0.520162 51.543350,-0.520124 51.543382,-0.520058 51.543431,-0.516694 51.546331)))
point: POINT (-0.518659 51.545256)
notes
entry-date: 2017-07-04
start-date: 2017-07-04
end-date

Your data is missing a tree-preservation-order.

The Tree preservation zone guidance explains how to fix the issue:

The reference for the tree preservation order that covers this zone.