Remember that any store shop or pub/restaurant is a private business who can refuse entry to anyone ( unless it contravenes legislation).
If your meeting is in say a village hall then the covid requirements of the building will need to be adhered to by the hirer( PC) as well as their own decisions. If anyone is not wearing a mask then the PC is not barring anyone, the venue are. If the venue sets out exemptions in the risk assessment then the council can allow them access.