The following should help you arrive at a price for your home:
Talk to your estate agent. Most estate agent's offer a 'free appraisal' service. Ask the agent to provide you with previous sale information from their database.
Use your online resources The Internet is a great way nowadays to glean information about surrounding properties
Get a registered valuation. This typically costs anything between £350 and £500 and can be a great bargaining chip later on with potential buyers. The registered valuation takes into account the sale price of other properties in the area and the chattels. Your bank can usually help to recommend a valuer in your area.
To get a quick idea of the current value of your property Mouseprice.com offers an instant market estimate for residential property
Your asking price should not be too high or too low as it may put-off potential buyers. You should probably think of a price range with the minimum price you would accept ranging to what you would consider a good price.