... especially those with multiple branches in the South East of
England especially London suburbs and the county of Surrey including
towns such as Guildford and Woking.

try this website its the National estate agent association. It has a
find an agent function and seems to list all the well known ones. You
need to use this with the post code function (ZIP) so I suggest you go
to www.multimap.com and decide on your particular locations and get
the relevant post code. Then enter into the above website and voila.

Many Estate Agents are members of the National Association of Estate
Agents in the UK http://www.naea.co.uk/
Click under "find an Agent" for agents in the location you require.
If you type in Woking or Guildford in the areas it will provide a list
of estate agents.
If you are browsing to purchase a property in a given region I
recommend www.primelocation.com
Once you have selected the area you want to search for properties on
the right hand side of the screen it enables you to register with all
the estate agents local to the area of your search.
There remain the very large and exclusive agents such as Savills,
Frank Knight and Hamptons - who all register their properties on
primelocation and with whom you can elect to register directly with.
I hope this answers your query.