FTTC expectations- should this happen?

[#1]

Hi,
Had extremely reliable and consistent HiSpeed Fibre Unlimited service for about a year (since launch), never once had it lost sync or misbehaved, consistently I
had 9mS latency and 43Mbps download speed.
Monday evening the service dropped several times including loss of VDSL causing DSL light on Openreach box to flash continuously. From Tuesday morning the service has restored, but now my speed has dropped to 38Mps with 28mS latency and slower web page loads.
I haven't logged as a fault as BT have been scheduled to do some infrastructure 'maintenance' in this area (Milton Keynes) this week. My concern is: has the BT 'maintenance' degraded my service permanently or should it recover. Does someone in PlusNet need to alert BT about issues with the infrastructure changes.
Any hints to get this back as it was? I have logged my routed off waited then on, and rebooted it. I have not touched the Openreach box.
Thanks

[#2]

Hi Frogger,
There's nothing wrong or needs reporting with the maintenance, though sorry it's caused a few disconnections for you:
<img src="http://ccgi.psmith12.plus.com/visradius/generated/image13717247475384.png"/>
This will be why the speed has dropped. Now it's stable again things should pick up within a couple of days, though if they don't please let us know and we'll reset the SNR for you to let the line retrain.