Well done again to Open Reach. my broadband dropped and internittently stopped, Open Reach Engineer came to my house 12th April 2017 as promised and solved the problem right away. He explained that the BT Server manager system had detected the "fault" caused by the defective Hub 4 and had not reset itself when the Hub6 was connected. The packages of data streamed to the hub had not been recieved due to the defective hub so the server had reduced the stream rate to compensate for an imaginary "defect in the cable"
Thank you again Open Reach for stirling work, Broadband now 4 times faster than a week ago and back to normal