Tree preservation zone

There is a problem

reference: TPO 0006 (1966)/A5
name: BALSHAM Parish
tree-preservation-order: TPO 0006 (1966)
tree-preservation-zone-type: area
geometry: MULTIPOLYGON (((0.306305 52.134855,0.306879 52.134843,0.306913 52.134784,0.306902 52.134739,0.306860 52.134700,0.306733 52.134641,0.306773 52.134630,0.306721 52.134596,0.306838 52.134377,0.306882 52.134331,0.306861 52.134323,0.307223 52.134216,0.307430 52.134163,0.307523 52.134149,0.307956 52.133999,0.308247 52.133880,0.308457 52.133760,0.308518 52.133739,0.308606 52.133734,0.308662 52.133787,0.308711 52.133808,0.309065 52.133757,0.309122 52.133831,0.309137 52.133827,0.309363 52.134037,0.309483 52.134131,0.309693 52.134187,0.309785 52.134194,0.309868 52.134222,0.309927 52.134227,0.310059 52.134216,0.310195 52.134184,0.310301 52.134170,0.310500 52.134168,0.310547 52.134185,0.310688 52.134339,0.310793 52.134433,0.311240 52.134792,0.311677 52.134587,0.311731 52.134633,0.311766 52.134707,0.311767 52.134723,0.311748 52.134757,0.311700 52.134785,0.310293 52.135448,0.309867 52.135525,0.308906 52.135925,0.307754 52.136143,0.307356 52.136200,0.307095 52.136229,0.307074 52.136203,0.306937 52.135876,0.306904 52.135831,0.306891 52.135824,0.306789 52.135845,0.306722 52.135850,0.306564 52.135576,0.306459 52.135392,0.306269 52.134946,0.306268 52.134874,0.306305 52.134855)))
point: POINT (0.308626 52.134971)
notes
entry-date: 2021-09-01
start-date: start-date must be a real date
1966-12-12
end-date

Your dataset is missing the start-date column.

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

The date that the tree preservation order came into force, written in YYYY-MM-DD format.

Example: 1984-03-28