Hi Guys, Thx for the input.
My neighbour's house is very close, in fact we are attached cos we are both sides of a semi

and there is a river between my house and the exchange.
I have now checked Kitz as suggested which says I am 1.05km away (direct) and 2.09km by road. (I have confirmed this with GoogleEarth).
I do have a BT line attached to the house but it has been disconnected for about 12 years (since I joined NTL/Virginmedia). I am hoping that if I go back to BT they will check the line out and not just switch it back on.
The cost of switching to O2 will be £25.50pm (£15 for 20mb BB and £10.50pm for BT line rent with free evening/weekend calls). So I would be looking for the O2 BB to perform better than the VirginMedia 10mb cable at the same price. Although taking the Traffic Management into account it could perform a lot less and it would still be worth going for.
I have had the 20mb cable since it came out and am reluctant to change to adsl but now they have put my price up to £37 from £25 I feel that I have to explore the other option.