Your data has issues

There is a problem

• 1 entry must have dates in YYYY-MM-DD format

Reference	Name	Designation date	Document URL	Documentation URL	Geometry	Point	Notes	Entry date	Start date	End date
CA-31	Bulls Bridge	Invalid date	https://www.hillingdon.gov.uk/media/3843/Bulls-Bridge-map/pdf/agBulls_Bridge_CA.pdf?m=1603207295180		MULTIPOLYGON (((-0.404439 51.502683,-0.406193 51.500762,-0.406277 51.500790,-0.406408 51.500737,-0.406615 51.500523,-0.406642 51.500520,-0.406998 51.500626,-0.407111 51.500635,-0.407462 51.500394,-0.407175 51.500285,-0.407442 51.500041,-0.406928 51.499883,-0.406629 51.499808,-0.406319 51.499758,-0.406272 51.499817,-0.406460 51.499903,-0.406030 51.500364,-0.405489 51.500913,-0.405468 51.500959,-0.405162 51.501284,-0.405122 51.501314,-0.404920 51.501527,-0.404908 51.501558,-0.404118 51.502424,-0.404122 51.502446,-0.403786 51.502803,-0.403723 51.502849,-0.403987 51.502834,-0.404022 51.502811,-0.404084 51.502795,-0.404165 51.502713,-0.404190 51.502705,-0.404249 51.502707,-0.404268 51.502689,-0.404439 51.502683)))	POINT (-0.405753 51.501087)		2026-03-13

How to fix this issue

Your dataset is missing the designation-date column.

The Conservation area guidance explains how to fix the issue:

designation-date

The date that the conservation area was officially designated, written in YYYY-MM-DD format.

Example:

1984-03-28

With dates, some data is better than no data, so:

• 1984 is fine
• 1984-03 is better
• 1984-04-28 is brilliant

How to improve London Borough of Hillingdon’s data

1. Fix the errors indicated
2. Use the check service to make sure the data meets the standard
3. Publish the updated data on the endpoint URL