[kinard]

Ridiculous that postcodes/uprns lookups are not open data (yet). hohum.

[callamdelaney]

They are in the UK but you have to have some magic understanding of around 15 separate files. Seems to be purposefully difficult.

[mrngm]

NL as well, but the source data has a couple of indirections before you get to the postcode.

It's doable, monthly updatable for free, but requires a bit of processing and understanding of the geo structures.