If you get your electricity from Powergen and have the tariff (sometimes known as 'no standing charge' - what a misnomer!) where they charge pro rata n pence/unit for the first x units per quarter and then another rate for remaining units, make sure they've done their maths right and allocated units correctly to each price band. They appear to have changed billing systems recently. The bill I received today had the split across different bands in their favour, allocating more units to the more expensive (first) band and fewer units to the lower p/unit band. It won't be a huge amount, but across several accounts Powergen might make a pretty penny. I did have to spend some time explaining basic maths to the person I spoke to until he understood what the issue was (and, slightly frustratingly, I could hear someone else - his supervisor? - whispering all the answers in his ear which he just relayed on).
Allan