I have also had to really wind him up about declarations of conflict at the beginning of the meeting.
All he has to do is to put it at the top of every agenda, asking if there for any conflicts of interest relating to items on the agenda and reminding members that are substantial statutory fines for failure to do. Something like:
Members to declare conflicts of interest relating to items on the agenda. FYI: Failure to do so can result in substantial monetary fines. (NSW Strata Schemes Management ACT, Schedule 2, Part 3, Section 18)
Most people reading the agenda will assume the strata manager put it there.
Surely there must be a solution for this other than having a blanket delegated authority?
The simplest solution would be for the committee to temporarily elect a new chair until such times as the incumbent has raided the biscuit tin. Any strata committee member can have multiple office-bearer roles.