NestLink publishes 34 UK map layers built from published open data. Each layer has its own page and its own sources, and every figure states where it came from and when it was retrieved.
How the layers work
Every layer attaches values to the same geography spine: postcode district, postcode sector, street block and individual property. Zooming in swaps tier, not map.
Where a source has no reading for an area, the map paints it neutral and the page says unknown. Missing data is never rendered as zero or replaced with a national average.