As for speeds of adsl it can be upto 8Mbps but in our experience this unusual not the norm.Things that infulance the speed you can get are distance from the bt exchange, state of the copper running to your site.If its been there yrs there will be corrosion and the grade of the copper itself.

In some areas there is an option for cable, this is currently the biggest comeriacl project going on in the Uk hence all the dug up roads What the cable provider is offer is effectively a network link as you would have in an office but on a huge scale know as a WAN (wide area network)The speeds that you gat on cable are quick up to 16Mbps at the moment and about to rise. But Cable has limited distribution at the moment and not really likely to go out into rural areas.