Most above miniscule technology businesses will already be using Ethernet over fibre, or leased lines.
For business use you get much better contention etc, and better support levels.
handy estimate of cost, £1000 per month.
Also talk to people like http://www.fluidata.co.uk/connectivity/
who do bonding, i.e. 3 or 4 slower ADSL lines, can be bonded to meet and exceed your 10Mbps requirement.