Thought I would make a positive post!
Our speeds were at 2mbps for ages, then they went down to 1.5mbps, it was that speed for many months before I decided to do something about it. I bought an iplate and a new modem cable and two new filters. I had some trouble, the new modem cable put my attenuation up to 61db from 58.5, I went back to the old cable and it went back to normal. So I bought a higher quality cable and it stayed at the same attenuation. Once I had fitted everything I was a bit dissapointed that my connection speed stayed the same.
A few weeks later I decided to ring Sky up and see if I could get my connection speed up, I rang sales first to deal with something else, then asked them about my connection, he said that I would need to speak to technical, so he gave me the number and told me what to press. Turns out I was put through to housing (Sky moving house support) but he transferred me to technical.
The man on the phone was friendly and reset my line after a short wait. It connected at 4096kbps, I was amazed as the best I had before was 2.9 and it didn't stay that high for long, around 2.6 I was able to get for a while. I told him I had never had this speed before and he said something could have improved at the exchange or on my line (perhaps me installing the iplate?) so then I asked him if he could put my upload speed up as it was 602k or something, so he was able to get it to 768k but said it might make errors but that it wasn't at the moment and told me to monitor the speed.
It went down to about 3.6 the next day, but then up to 3.8, 3.9 and 4000 exactly after some restarts (we had to turn the electric off a few times - fitting new sockets!) so that was pretty good. Had to turn electric off again today and its connected at 3.9.
I saw the Noise Margin go as low at 4.2 but its at 6.1 at the moment. A strange thing is for as long as I can remember I've had 58.5 attenuation, but when I got put up to 4mbps, the attenuation went down to 55, last few days its been 56 and looking at it now its 57.
He also said something about me being on 8mbps but I'm getting 4mbps, I'm on Sky Broadband Unlimited LLU so I've no idea what he was on about (i.e I should be getting up to 20mbps), unless I misheard him.
Well thats my good experience with Sky Broadband!