Within this section of the site, you'll find a listing of all the Estate Agents in Avon broken down by town that I can find. If there are anymore out there that I don't know about, then feel free to let me know and I'll add those details to the list.
If you're looking to buy a house in a particular area, then you need to identify all the houses in that area and see what houses are available. It is important to keep visiting all the estate agents as often as possible as new houses come onto the market all the time.
If you're selling a house, then get a valuation from as many Estate Agents as you can, I believe that they recommend that you get at least 3 quotes. Also, each Estate Agent will probably have different fees so take that into account as well as how you feel about the Estate Agent. If you think that they're not going to work hard selling your house, then walk away.