It sounds like, from your 2 postings that your council need to get a locum in to cover the clerk who is on long term sick leave. It would make the council's life easier rather than having to patch up issues as they arise.
The person acting as the Clerk, when formally appointed by the council to undertake this role, can publish an agenda - the only issue I can see is that the council hasn't formally appointed anyone. I would suggest that in this instance, the Chair calls an extraordinary meeting with the purpose of appointing a Clerk / RFO either from their own ranks or getting a locum Clerk in, and then continuing business as usual from that point.