Tree preservation zone

There is a problem

reference: TPO 0006 (1966)/A13
name: BALSHAM Parish
tree-preservation-order: TPO 0006 (1966)
tree-preservation-zone-type: area
geometry: MULTIPOLYGON (((0.314827 52.133709,0.314849 52.133687,0.314889 52.133681,0.315364 52.133661,0.315319 52.133609,0.315385 52.133585,0.315539 52.133576,0.315654 52.133559,0.315827 52.133516,0.315856 52.133498,0.315855 52.133449,0.315824 52.133338,0.315782 52.133251,0.315777 52.133197,0.315798 52.133183,0.315882 52.133185,0.316176 52.133151,0.316241 52.133276,0.316263 52.133297,0.316303 52.133367,0.316406 52.133512,0.316362 52.133521,0.316387 52.133554,0.316428 52.133543,0.316556 52.133742,0.316551 52.133768,0.316464 52.133900,0.316459 52.133960,0.316497 52.133980,0.316665 52.134022,0.316893 52.134111,0.316931 52.134119,0.316969 52.134109,0.317168 52.134529,0.317488 52.135147,0.317512 52.135208,0.317469 52.135231,0.317369 52.135258,0.317048 52.135306,0.316523 52.135406,0.316374 52.135419,0.316195 52.135413,0.315684 52.135486,0.315247 52.134567,0.314843 52.133757,0.314827 52.133709)))
point: POINT (0.316139 52.134453)
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