I have seen the stump of Walton Castle at extreme low tide off The Dip at Felixstowe but have never thought of taking a photo of it, here is a good website giving its history
http://www.wuffings.co.uk/WuffSites/Walton.html
I am unsure whether Little Wenham is a Hall or Castle but in case it is the latter I will include this here also
Little Wenham Hall/Castle is reputed the oldest habitable brick building in Suffolk and one of the oldest in the UK
http://www.castleuk.net/castle_lists_east_anglia/169/wenhamhall.htm