I recently looked into this my self, and wrote and asked a few companies. My idea was to buy two batteries, one on, one charging. The set up below should power( I haven't bought it yet) a varierty of 12v appliances. Televisions and fan heaters are out though - too much start up power needed. Cost around £250.
The Battery
http://www.mdsbattery.co.uk/shop/productprofile.asp?ProductGroupID=1162 The solar panel
http://www.mdsbattery.co.uk/shop/productprofile.asp?ProductGroupID=1093the Inverter
http://www.mdsbattery.co.uk/shop/productprofile.asp?ProductGroupID=1263I hope this gives you a few ideas. The company replied to my email promptly if you have any questions.
It would be interesting to find out what you decide on.
joblot