Tree preservation zone

There is a problem

reference: TPO 0006 (1966)/A29
name: BALSHAM Parish
tree-preservation-order: TPO 0006 (1966)
tree-preservation-zone-type: area
geometry: MULTIPOLYGON (((0.313897 52.131941,0.313887 52.131919,0.312004 52.132001,0.311807 52.131526,0.311769 52.131414,0.311707 52.131169,0.311021 52.131199,0.310971 52.131194,0.310818 52.131200,0.310651 52.131219,0.310650 52.131276,0.310500 52.131289,0.310433 52.131144,0.310189 52.130670,0.311181 52.130446,0.314782 52.129659,0.314990 52.129953,0.315249 52.130346,0.315376 52.130554,0.315502 52.130804,0.315686 52.131246,0.315430 52.131319,0.315542 52.131446,0.315395 52.131438,0.315298 52.131417,0.315178 52.131403,0.315099 52.131402,0.315022 52.131428,0.314942 52.131439,0.314856 52.131424,0.314863 52.131447,0.314973 52.131522,0.315078 52.131772,0.315152 52.131825,0.315192 52.131870,0.315141 52.131894,0.314799 52.131912,0.314316 52.131912,0.313897 52.131941),(0.314488 52.131000,0.314503 52.130991,0.314488 52.130978,0.314472 52.130985,0.314488 52.131000)))
point: POINT (0.313289 52.130927)
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