Technically it’s possible providing the Pole is within 68m.
You could have other issues though as in Planning Stage for FTTP your property is assigned a NAD Key, which is associated with a specific CBT, which in turn is connected to a Particular SASA, which and most importantly is assigned to a Head End Port.
If the CBT on the Pole out front is on the same Head End then they could easily put in a Routing change on the day of Installation.
If the two CBT’s go back to different Head Ends though they it would need to go back to Planning for a NAD Key Reset and depending on Capacity at the adopting Head End Slot they might not be able to do it.
If an Alt Net is available and you are going to use them , it’s not appropriate or allowed to discuss other operators on this BT Customer forum , FWIW , they will have their own processes and procedures, so it would be between you and them the manner in which they provide service, even if they use Openreach infrastructure via PIA , to locate their equipment.