This corresponds to what looks like a 5 hour outage (100% packet loss according to ThinkBroadband) on the 7th September. As a member of SamKnows I can also see the graphs prior to the 7th September and after the 7th showing the speed drop. BT Wholesale checker reports I am on a 74Mb/s or 77Mb/s profile, can't remember and can't re-run the test for a while.
Problem ticket raised with PN on Saturday, waiting to hear back.
Edited by Skilty (Tue 24-Sep-13 09:43:43)