Hi there, I'm not that technical on phone deals my parents are with BT and I'm with ADSL24 as my ISP.
I honestly don't blame you about leaving Virgin Media ADSL. Some years ago I went with them I was appalled with the speed and service given I left them after 10 days.
You can have a look at the ratings on the click here website about them shocking stuff I have to say.
Before we go any further what is the Make of your modem/router? I need to see your full line stats to determine what speed you can get on your line.
Can you tell me what Samknows says is at your exchange? Post back the full results.