My router is permanently on. As I said earlier, the main problem is not speed, bad as it is, it is the slow response of web pages. I can have a download speed of around 2 Mbits/sec but still have to wait for pages (from even major sites) to download. The BT.com home page for example, just took 10 seconds to first respond and a total of 14 seconds to download fully, yet my download speed is 1.99 Mbits and ping (to London) was 43 msecs.
Re test for noise by the way, there was no noise on the line.