How long to get back to normal speed?

[#1]

On Sunday evening whilst I was on the phone I noticed that part way through the call the line suddenly became noisy. . This seemed to initiate a series of disconnections with my broadband. At least 6 occurred (maybe more) and my speed dropped from a steady 12.0 Mbps down and 0.75 Mbps up to about 9 Mbps and 0.09Mbps. I assume the DLM had caused this. The line seems stable again and I can hear no noise on the quiet line test now so how long will it take for the speed to return to normal? If the noise returns I guess that I will have to use the test socket and change  the filter and router before raising a fault.  

[#2]

Provided the line remains stable, and everything is in order it can take a few days for sync to change automatically.
I've tested your phone line as a precaution and this looks to be OK. Having done this, I dropped your session (which won't cause DLM any issues) so I cannot check what you are currently syncing at. If required, we can change your SNR which might improve things.

[#3]

Thanks. Speed back to normal.

[#4]

Excellent, thanks for letting us know.