you just need your most recent bill handy so you can tell them a few numbers (like what that they charge per (whatever unit of measuring electricity is) lol)
Thats the problem we haven't had an electricity bill in over 15 months and then it will be a new house again with different features etc so I have no idea what our usage will be. I do remember that my bills (usage) always seemed to be alot less then everyone else I knew when we where connected so I am not sure that them (enery watch for example) working out our usage using a family of 4/5 and 3 bedroom/2 living rooms will be accurate IYKWIM and since the rates change after the first 1000 or 1500 kwhs used it could mean alot to our final bill.
I am thinking of signing up to one with good rates that has no contract/no exit fee for the first couple of bills to see what our usage is then calling enery watch to make sure we have the best deal.... ohh I am just babbling now .

blessedatlast - the power is most likely switched off, if you call them ASAP today they should be able to switch it on in time.