I spoke to retentions today, and got nowhere, but was told that although they knew my area was over-subbed, the reason it hadn't been upgraded was likely because they couldn't get planning permission from the council to re-dig up the roads and pavements and replace the cables!!!
So there you go, Manchester council are to blame for the poor speeds in Fallowfield, and not as I had suspected, Virgin and their annoying practice of over selling it to everyone in the area
Their nonsense knows no bounds. The guy even told me he didn't blame me for wanting to leave and didn't try to convince me to stay at all. Although laughingly he tried telling me ADSL wasn't as reliable as it relied on distance from the exchange. Yeah, because VM's service has been soooooo reliable for me at the moment...sigh.