Got the problem sorted - There was a major fault at the Bratton Exchange (they could have told me I'm only 1.6 km away). The lady on the Indian Call centre went through a complete reset - and it worked ! Everything works much faster now ! But roll on BT Infinity when it gets out in the sticks (but don't hold your breath ! It may be some time away. She is also upgrading my BT Router 2, to a Mk 3 model.
Samsung Galaxy S8 review