The new Companies House API is in early Beta. We're giving software developers early sight of the API to help them get up to speed with what we're doing and plan development, and also to help us catch issues early.
As a result, some API resources are in a state of flux, and are being cleaned up and made consistent.
For example, the search results resource is going through a big re-factor to make it much simpler to consume.
We will post notifications about pending change over the coming weeks.