Northern Wheatear (Oenanthe oenanthe)
Only the second time I've ever seen this beautiful ground foraging bird as it's usually a rare and brief visiter to Sussex, stopping as it sometimes does in early March on it's inward migration from Africa on its way to the north of the British Isles and beyond.
Although late, it would be too optimistic i think, to believe there may be nesting couples nearby.............but you never know?
More information here:

The northern wheatear or wheatear is a small passerine bird that was formerly classed as a member of the thrush family Turdidae, but is now more generally considered to be an Old World flycatcher, Muscicapidae. It is the most widespread member of the wheatear genus "Oenanthe" in Europe and Asia.