Also, don't forget that if you live in a Conservation Area or in a Listed property the fence you put back must be the same as the one you take out other wise you will need planning permission.
The same applies to height. You can't make a fence taller without applying for planning permission. See my post on the Independent property blog:http://blogs.independent.co.uk/2013/02/13/all-you-need-to-know-about-permitted-development-%E2%80%93-part-2/
26 Mar 2015 18:01
You mention about not using too much concrete, especially in small gardens - but you need to use the recommended amount to ensure the fence holds firm. Another option that requires no concrete at all, are Fence Fins. They're a new invention - metal braces that are simply hammered to the post and sit under the ground holding the fence against the force of the wind due to their unique shape. They're invisible after installation and you can plant right up to the fence. Have a look on the steadypost.co.uk website.