thats your issue then same as my relative had once i changed the channel it was back to about 7mb you need to see if you can find a guide for your router tom or ring sky helpline they will talk you through it but if your like me i hate talking on the phone i just find online guides and follow them.
http://help.sky.com/articles/speed-up-yo...ss-channel
http://help.sky.com/articles/speed-up-yo...ss-channel