Can you run this checker and post back a screen shot of the results. Make sure you delete your phone number before posting.
and use this speed tester then scroll down the page and carry out the further diagnostics and post back a screen shot of all the results including your IP profile for up and down. This test must be done with a wired connection.
If you have a Homehub 5 can you post the stats from 1-12 by logging onto the Homehub management pages then troubleshooting > helpdesk. http://bthomehub.home/
If you have the Smart Hub, (Homehub 6) can you go to hub manager then advanced then technical log and post the stats. http://bthomehub.home/
Is there any noise on your phone calls? Dial 17070 and select option 2, there should be no noise between the announcements.