Check out the rateable value of your house:
http://vla2.nics.gov.uk/sl5/search.asp?submit=form
I got a letter through the door yesterday to tell me that someone from the rates agency had called and could I call them. I am loathed to do this, my rates are in some blackhole and are a paltry £18.00 a month, my neighbours are a lot more.
I don't know why this may be, you can compare your rateable value with those in your street at the above url. It looks like my secret is out now though, they are on my trail, thankfully the civil service are on strike, I have tried to call them three times today and I just can't seem to get through to tell then they should be charging me so much more, I am trying so hard aswell!!