Article 4 (g) does give the definition of daily rest periods under ‘normal’ circumstances i.e. the vehicle is single crewed.
Article 8.2 requires that a driver (single crewed vehicle) takes a daily rest period within 24 hours of ending the last rest period (daily or weekly). The second paragraph of 8.2 states that a regular daily rest is at least 11 hours and a rest period of between 9 and 11 hours will be considered to be a reduced daily rest period.
Article 8.5 basically cancels out both paragraphs of Article 8.2. It puts forward a very specific case; i.e. a driver involved in multi-manning, which is defined in Article 4 (o). The wording in 8.5 effectively replaces the wording contained in 8.2 where the vehicle is multi-manned. So, if the vehicle is multi-manned you ignore the wording in 8.2 and substitute the wording in 8.5 instead. There is a new length of a ‘day;’ 30 hours and a requirement that a rest period of at least 9 hours be taken within that period.
European Regulations are hierarchical in structure, what comes later overrides what is originally written. In this instance daily rest is defined then later modified in particular circumstances.