Is there an Openreach ONT in the flat ( a white mains powered box) ?
if there is , is the PON light lit and steady green, if that’s the case , presumably the address records haven’t worked their way through the system yet that’s why you can’t order , FWIW , looking at that postcode many of the addresses seem a little shambolic in that there is no common format to the address structure , is it’s possible the development has changed hands , or suffered other complications that changed the name of the properties, so it’s possible the final recorded addresses are now different , making the addresses unmatchable with the way the properties were originally going to be known ?
…..if there is no Openreach ONT in the flat , then the developer never approached Openreach about putting Openreach network in the development , so you would need to ask the developer what they intended as far as broadband, perhaps they had a different network provider lined up and deliberately excluded Openreach , so that other network provider is fitted and you need to use them or this other network never materialised leaving the addresses with no availability at all .
