Speed decrease...

[#1]

Following a couple of months with both mains power and router faults that caused me to drop connections several times a day, now that all is well I noticed that my speed has fallen from around 47Mb/s to around 40Mb/s.
Is there some sort automated line self-adjusting in use that may have throttled my line speed to compensate for the constant interruptions? If so, can it be reset and how do I get that accomplished please?
Kind Regards

[#2]

DLM is what looks at the line and if it feels that the line isn't stable enough it will lower speeds by adding interleaving and or banding to keep it stable, router faults wouldn't cause speed loss but loss of power to the modem could cause issues if it happens often.
Sadly you cant get a reset unless a physical fault was repaired on either the cab / exchange or the line even then it's up to the engineer to request one.
if none of that happened you will have to wait for DLM to increase the speeds again once it feels the line is stable enough to handle it,  how long this takes varies it can be days it can be weeks it's a waiting game i'm afraid. 

[#3]

Thank you. I'll just have to be patient.
Terry