Re: Could this become the official UK postcode and address database?
Well certainly three or four years ago there was a very good OS product called AddressBase Plus which was managed by a combination of Royal Mail (for mapping of postcodes and delivery points) and various local authorities. The idea was that it held details of every structure (house, bus stop...) in the UK for use by people like the emergency services.
It's a massive data set, but very high quality.
Back then it didn't have elevation data so to get the heights of things we used to overlay the Environment Agency's LiDAR dat. It would appear that elevation data is now included.
I guess the data used in the AddressBase product is what is used to drive the new API.