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: ZZZZDVESXE466
name: The Amersham Rural District Council (Little Kingshill) Tree Preservation Order No 8 - 1971 [No 8 of
tree-preservation-order: undefined
TPO/1971/008
tree-preservation-zone-type
geometry: MULTIPOLYGON (((-0.695083 51.684012,-0.694814 51.683846,-0.694633 51.683806,-0.694584 51.683811,-0.694646 51.683859,-0.694777 51.683954,-0.694949 51.684066,-0.695046 51.684122,-0.695102 51.684148,-0.695170 51.684185,-0.695221 51.684215,-0.695306 51.684271,-0.695343 51.684293,-0.695691 51.684544,-0.695789 51.684609,-0.695937 51.684690,-0.696053 51.684735,-0.696111 51.684754,-0.696260 51.684855,-0.696349 51.684902,-0.696500 51.684970,-0.696725 51.684833,-0.696776 51.684794,-0.696848 51.684731,-0.696965 51.684623,-0.697063 51.684529,-0.697248 51.684337,-0.697585 51.684002,-0.697657 51.683937,-0.697762 51.683826,-0.697816 51.683764,-0.697856 51.683715,-0.697903 51.683647,-0.697932 51.683600,-0.698017 51.683473,-0.698017 51.683458,-0.698005 51.683441,-0.697978 51.683441,-0.697959 51.683444,-0.697931 51.683466,-0.697678 51.683799,-0.697323 51.684155,-0.696822 51.684642,-0.696676 51.684788,-0.696564 51.684880,-0.696498 51.684907,-0.695898 51.684556,-0.695583 51.684347,-0.695083 51.684012)))
point: POINT (-0.696324 51.684283)
notes
entry-date: 2010-02-18
start-date: 2010-02-18
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.