Hiorne Tower in Arundel Park, Arundel. There is no significant information about the tower online and I don’t recall being able to go in when I visisted. There are a couple of links on Google saying it was a location for Doctor Who at some point. There are also a few links about it being haunted and similar tales.
For me it was a stop along a walk from Time Out Country Walks 1, walk 32, Arundel to Amberly. I can’t find a current printing of the books, though old copies are on Amazon. I have always used and recommend the website http://www.walkingclub.org.uk/