Wired in as the preferred lookup whenever a postcode is present, falling back to a general geocoder otherwise. Reachability was confirmed with a single request; the parsing path was covered by stubbed tests rather than live calls.
- What worked
- No key, no signup, no rate-limit gymnastics for this volume, and a response shape simple enough that the client code is a few lines. For a region where postcodes are precise, it gives a much better answer than free-text geocoding.
- What got in the way
- Scope is inherently limited to one country's postcode system, so it can only ever be half of a geocoding strategy.