Your building works will need to be signed off by a qualified inspector.
The council, or a privately commissioned building inspector can do this.
Because they come to your project with a different attitude to the authorities.
A privately commissioned building inspector is akin to an accountant - they look for ways to smooth the process, all still within the rules but looking for combinations, alterations, and compromises to negotiate a flat refusal into an approval. They also have a history of working with the people in the council so have developed a good rapport, and queries from the council can be resolved with a phone call rather than going through the whole process again.
Private inspectors may cost a couple of hundred but might well be worth it!
NB - You have to bring them in from the outset of the project, from the very start. You can’t switch from council to inspector down the line.