There are several reasons your address won’t appear until the property is complete, and several datasets used by the utilities and businesses.
Properties are addressed by the local authority and entered on the Local Land and Property Gazeteer. Each local authority feeds their LLPG into the National Land and Property Gazeteer daily.
Best practice is to allocate addresses as soon as possible, usually upon notification of commencement to Building Control but some LA’s leave it much later. The LLPG/NLPG has a classification system that allows properties to be added at any point from the submission of a planning application.
Postcodes are allocated by Royal Mail, but they are added to the LLPG/NLPG once allocated. RM have their own dataset called the Postal Address File (PAF) which consists of two parts - the standard file and the Not Yet Built file. The LA will notify RM when they address a property, RM allocate a postcode and add the address to the NYB file. RM will only move properties from NYB to the standard file when they are ready to receive mail. RM sell the PAF to utilities and insurers etc, it’s probably cheaper than buying an NLPG feed.
The other dataset that is used to determine residential properties is the Valuation Office Agency database of Council Tax bands. The VOA only allocate a Ctax band once the property is occupied and somebody has registered to pay Ctax.
Developers are universally hopeless at notifying LA’s when properties are occupied, or ideally a few weeks beforehand. An email or call to the council from yourself should get things updated pretty quickly.
