Hmm the broadband is up and down, up and down. I'm presuming the line is being trained - any ideas how long it will take to settle down?
If you are on their upto 20 meg (LLU) broadband, then DLM runs pretty much from when you go live and can continue to run for upto 10 or sometimes 14 days.
DLM basically determines what speed your line can reliably hold/manage.
If you log into the Sky website from the below link, you will see so far down that page 'Line connection testing completed on'.
http://mysky.sky.com/portal/site/skycom/mysky/getbroadband
DLM ran for me for 7 days, but everybody is different. I found that while DLM was running, my router pretty much rebooted (due to DLM) at around 2:30am. During DLM your speeds and connection can be up and down.
If you log into your router by entering
http://192.168.0.1/ in your internet browser, then click on SHOW STATISTICS, you will see port WAN, port LAN, keep an eye on these and you will be able to see when/if your router has been rebooted, basically the figures that will be shown, will only be showing a figure of a few hours. So if you check these before you go to bed and then check them again in the morning, you will be able to see if DLM has rebooted your router during the early hours of the morning.