You need to call and speak to BT.
This is a customer to customer forum and only the mods are BT employees but they don't read everything and don't have access to customer accounts.
This is a BT residential customer to customer forum. Your post does not go to BT. The only BT staff are the forum moderators who do not necessarily read all the posts and they do not have account access.
Have you tried using the One Touch Switching
https://www.ofcom.org.uk/phones-and-broadband/switching-provider/simpler-broadband-switching-is-here
If there is an address issue you will need to get your present provider to correct it or contact BT 0330.1234.150 and place an order and ask if they can raise an ORDI request.
Have you reason to suspect an address issue, perhaps problems in the past with deliveries or you were advised the development plot number / street number misaligned ?
If you put your address in here does the return show ONT exists with active service ?
https://www.broadbandchecker.btwholesale.com/#/ADSL/AddressHome
Supposedly there is the option to use the ONT serial number to locate the address with this ONT , but this would need you to call , and for the customer service guide to have the necessary system knowledge to locate the existing service using that info .
Obviously if Sky were the first provider to supply service to the address , they obviously managed to raise an order so it’s possible but it may need manual intervention