I know that at least with NTL, if you sign up then move 6 months later to an area that's unserviceable, your contract is automatically cancelled... and if you move to another area that IS serviced by them you can transfer your service for free.
I don’t know if you’re scared of a contract, period (for any amount of time) or you were just worried about the 12 month thing…. either way, hope that helps!!