It’s really the developer you need to speak to , what provision have they made ( if any ) for broadband, either copper or FTTP ….you say there is no ONT that you can find , in which case is there a NTE5 type master socket ( Openreach branded ) , if there is , then that suggests OR were involved at first fix , although it’s also possible that the developer simply obtained OR branded equipment from a different source …if there is a generic ‘phone socket ‘ or no socket at all then there is a good chance the developer has done nothing at all and assumed it would simply need occupants to order and the provider would make the necessary network available…..was this a one man band type developer , the smaller the developer the less likely any contact has been made with Openreach.
As a reasonable amount of time has elapsed, if the Royal Mail website shows your new postal address then it may have filtered down into the BTwholesale checker , put the ( correct new ) address in here and post the results,
https://www.broadbandchecker.btwholesale.com/#/ADSL/AddressHome
If the building was a care home and has been converted to a relatively small number of flats then I would imagine it wasn’t a particularly large care home , was it a converted house , that became a care home and now flats ? , is it possible to tell what the previous method of service was ( like an area served by telegraph poles ) if it is a generally ‘overhead’ area and telegraph poles are close by , can you see a line of sight route an overhead cable could take to get into your individual flat from a near by pole ? .
Gold , Silver and bronze addresses are in part an indication of service being available in the past , it’s possible that when it was a care home it was a Gold address , but now isn’t , generally if an address cannot be matched to existing lineplant it’s not a Gold address , it’s not an area I’m familiar with but silver and bronze almost certainly need a survey , if it’s possible to serve from existing lineplant , like a nearby pole , that information is used to progress the order , if however the only way to provide service would be with coordinating with the developer/ leaseholder/ building manager etc , then cancelling the order is understandable, why be on the hook for compensation when the problem is not of BT or OR’s making , developers are under no compulsion to use Openreach , and in some cases make a decision to deliberately exclude Openreach to do a sweetheart deal with another provider, if that’s the case , ‘BT’ won’t be available and if the other network as failed to deliver , that’s between the developers and them , and you and the developer.
If you were promised connectivity and there is none , ultimately it may be for your solicitor to make representations to the vendor about this
