When i had my line speed dropped from 8mb to 6mb it was because even tho i had an 8mb connection (the test was done about 10.30am) my thru-put was about ...
Already mentioned this in another thread, so apologies for repeating myself, but it sounds like you've got the same problem i had when i was with Bulldog LLU.
Have you had a line distance test performed ?
I used to be a Bulldog LLU customer on their "uptp 8mb" service. They switched it on at 8mb on time, and i couldn't get a stable co ...