Are you sure they are phone sockets and not an Ethernet distribution network , often with properties on new sites , the developer puts the ONT location in a awkward place ( cupboard under the stairs for example ) but they also provide Ethernet connectivity from under the stairs to several places , like behind the TV location, or into a bedroom ( or other rooms ) …that way , if the customer wants , they connect the ONT under the stairs , to the appropriate Ethernet socket ( also under the stairs ) and at the other end of that Ethernet extension , they can plug in the router into that Ethernet socket in a better location , basically so the router doesn’t need to be next to the ONT ….sometimes the developer provides the sockets but it’s a paid for extra , so if the client didn’t pay for Ethernet, the sockets exist but are not connected.
Similarly , if they are phone sockets , you may find that you can plug the phone port ( with the appropriate cable ) of the SH2 into one of the wall sockets near the ONT , and plug your home phone into a socket at the other end of that extension cabling ( in the bedroom or living room etc ) that way you don’t have to answer the phone by climbing into the under stairs cupboard , but have it in a more convenient location.
Ultimately though , they are your sockets , nothing to do with BT or Openreach, and if it’s a new build , the cabling will not be visible ( installed before the interior walls were put up ) so why would you want to remove something hidden from view anyway , if the sockets themselves are not wanted you could remove them and re plaster but that seems somewhat unnecessary
