However, you really should get the address of the Community Hall registered with the Royal Mail.
Their database is used for lots of purposes not just delivering mail.
https://www.royalmail.com/personal/receiving-mail/up...
It shouldn't be, there are perfectly good databases for non-postal premises and other objects.
Unique Property Reference Numbers (UPRNs) are allocated by local authorities and Ordnance Survey.
Local authorities have the statutory permission to name and number every street and property in Great Britain and also allocate UPRNs to other objects.
Ordnance Survey identifies features in the landscape that might not have a ‘normal' address and includes them in its AddressBase products.
Openreach take data from multiple databases, to quote their Best practice guide to Address Management
"Address Matching is a pre-order Dialogue Service exposed to CPs which helps to streamline the ordering process by using addresses recognised by Openreach systems, or by creating temporary addresses. This dialogue service queries the Openreach NAD system and presents addresses known to Openreach and addresses in the Postal Address File (PAF), AddressBase Premium (ABP) or Pointer which are unknown to Openreach in order to identify whether a service request is against an existing known/matched or new address."
and
"Openreach maintains a version of the Postal and non-Postal addresses and displays updated addresses through the Address Matching Dialogue Services. Openreach receives and processes PAF updates 6 days a week from Royal Mail, and non-PAF updates every 6 weeks from Ordnance Survey / Pointer, with these updates exposed to our customers for both Gold and Silver addresses. Unique Property Reference Number (UPRN) and Site Classification attributes within an address are also processed and exposed every 6 weeks in line with updates from Ordnance Survey / Pointer."
So people in Openreach and at communication providers insisting on their being a PAF entry is incorrect, likely due to lack of training.