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: ZZZZDVESXE454
name: The Amersham Rural District Council (Windmill Plantation, Amersham) Tree Preservation Order No 9 - 1
tree-preservation-order: undefined
TPO/1972/009
tree-preservation-zone-type
geometry: MULTIPOLYGON (((-0.621242 51.678062,-0.621170 51.678137,-0.620926 51.678347,-0.620041 51.679174,-0.619154 51.679985,-0.622191 51.680694,-0.624031 51.681109,-0.624931 51.681331,-0.624920 51.681313,-0.624885 51.681096,-0.624778 51.680691,-0.624775 51.680628,-0.624783 51.680613,-0.624813 51.680602,-0.625338 51.680608,-0.625580 51.680577,-0.625878 51.680551,-0.625982 51.680533,-0.626118 51.680486,-0.626366 51.680368,-0.626624 51.680216,-0.625905 51.679892,-0.625209 51.679649,-0.624771 51.679472,-0.624278 51.679310,-0.622744 51.678848,-0.622578 51.678788,-0.622380 51.678695,-0.622262 51.678619,-0.622107 51.678491,-0.621974 51.678361,-0.621914 51.678290,-0.621883 51.678267,-0.621728 51.678210,-0.621242 51.678062)))
point: POINT (-0.622679 51.6798)
notes
organisation
entry-date: 2010-02-18
start-date: 2010-02-18
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.