Before I started in building control, the 'regulations' were a short book of technical rules. Now they're a thin set of legal requirements, couched in terms such as "reasonable provision". These are backed up by a series of quite fat 'Approved Documents' & secondary guidance, all of which is meant to provide 'the designer' with flexibility to follow innovative solutions.
All of which means that there is no 'text book' to quote from; each authority, team, or individual surveyor has to interpret the guidance in their own ways.