Were with Lloyds TSB would you believe for duel fuel then they passed across to Scottish Power who have been ok to be fair. They try the old chestnut of we're increasing your monthly direct debit fee as you've used more gas, this is after the winter quarter. So phone call later informing them that no, you're not doing that and making interest on the money that you WILL gain as summer gas usage will obviously be less, they agree. I just pay any additional charges above and beyond the projected usage to keep things level.
Now do it all on-line and they gave a good discount for doing so. Just make sure you have old statements to hand.
Can't comment on the change over from Lloyds to Scottish Power as it was all done in-house by them as it were.
Chris330d - Good info btw.