Thank you all for your feedback!
I must admit I am struggling to understand what happened as a result of the Openreach tech's visit.
Prior to that "everything worked".
I would have argued that after the visit we also had broadband, but with dataplans on mobiles and tablets, it may well have been that we didn't actually access the landline Internet service.
Support staff added to the confusion.
Who requested the visit, was it as a result of a broadband fault you reported to BT?
What was happening on your BT Home Hub?
Did you contact BT afterwards to tell them that it was not working after the visit?