Hi BM
Is it possible the new meter has been wired in the wrong way round? SO night usage is being read as day???
Can someone take regular readings from their meter? Say 8am and 8pm each day.. then see if the night usage is higher or not... as if they are frugal it should be easier to see when its being used...
Also - calculate what the kWh are based on the rate they are paying...
Another good forum I have found (apart from this lovely one) is
http://forums.moneysavingexpert.com
There is an electric bill section! With lots of experts who could help!