East Sussex County Council (ESCC) now have a page listing circular walks in the county. There are nearly 40 listed ranging in distance from 1.5 miles to 9 miles.
They also have an app which you can download to your smartphone for use with these walks. I have not yet tried out the app but will report back when I have the chance.
You can find details of these walks and download the app by clicking/touching/swiping here