Welcome to the forum and sorry to hear you're getting poor speeds. I've just checked your connection and noticed 2 issues. First there is a contention fault in the area under ticket F004215042 which will cause poor speeds at peak times and is due for review 15/03/17.
The other issue is that your upstream power levels are too high which will cause poor speeds and intermittent connection. We'll have to get a technician out to adjust this and I've just sent you a private message to arrange the best time. To view your private messages just click the envelope at the top of the page.