It took, as I recall, 6 or more weeks of pawing through the fixes last time.
EDIT:
I seem to be holding steady at about 8 Mbps but have a lot of heavy snow-laden cloud cover.
When you were experiencing the slowdown, were both boxes at the top of the SCC green?
(Sorry, I couldn't resist)
For someone that normally has fantastic speed, it's horrendous. I guess no Peaky Blinders for the time being.
I hope they can figure out what's going on fairly quickly.