Astun have set up a National Address Search web service, which is based on the standard Address Search Request used by iShare. The National Address Search service has been populated with national coverage of Address Base AddressBase® Premium data. At present it is provided on a beta service.
...
As added security Astun would intend to restrict the above endpoint by IP address and whitelist queries from either (i) the Council network or (ii) the hosted CRM platform. This would depend on the integration implementation - i.e. whether queries are direct from the user's browser (e.g. JavaScript calls direct to our web service), or via the CRM server (proxy). Basic authentication would only be suitable for proxy requests, as credentials should not be embedded in JavaScript code or entered by users. Further discussion is required between Astun and Walsall / CRM provider.
Licensing
The Council is responsible for ensuring that any contractors are fully compliant with OS Licensing arrangements for Address Base AddressBase Premium and legal obligations from those license licence arrangements. The service should only be used for Council specific work, and not for any other address searches by the contractors with whom the Council are engaged.
...