If the Openreach ONT PON light is steady green, then regardless of the address data the connection is ready to go…,the BT FTTP team should be able to use the serial number of the ONT to arrange BT service, you could search the forum for their contact number.
As far as the address being wrong in ISP’s lists of addresses ( which in itself is based on the Post Office data set ) , I know of an example where the developer , after advising the relevant party’s , the relationship between plot numbers and the final house/street numbers , deleted a plot so the house numbers were 1 number out , ( so as a example, plot 15 instead of being house No.30 , became House No29 , causing confusion) and another where at a tee junction within the development , where two different road names intersected, the developer presumably tweaked their plans , and although the front door and garage faced onto one road and this was the address it was to be known by, the builder inexplicably named it after the other road that the side of the house faced, so the addresses being messed up may be the result of the builder not doing as they originally indicated, but as said, the S/N of the ONT should be discoverable, and should be sufficient to get service started, ordering on line may be impossible until records are corrected , and the regular customer services may struggle, but the appropriate team should be able to raise an order for you.
If a router needs to be delivered , the delivery person may have some head scratching before identifying your property ….quite often on new builds, especially those moving in in the first phase, put an address sign in the window as the developer hasn’t yet put up street signs, and the buildings only have ( at best ) a sign with the plot numbers on them.
