As you are being offered an appointment slot , it’s assumed that you need an ‘full’ installation , it’s possible that if the property has had ‘BT’ type service in the past , then that can be reused, but if not , then depending on what type of area the property is in ( overhead with telegraph poles , or underground cable ) there may need to a hole made to get a cable from the outside to the inside , and a master socket fitting etc,
If address hasn’t had a working BT type line for quite some time , even if there is evidence of the previous ‘line’ , like a master socket, dropwire from a pole ( if overhead ) it cannot be assumed the line will simply come back into service , but it may , in which case the installer has a relatively easy job
