Harthill Grange and Harthill House
on Hewelsfield Common

http://www.old-maps.co.uk/
co ords 355316,202307

and the modern use of the site.
http://www.harthill.co.uk/index.htm

http://www.british-history.ac.uk/report.asp?compid=23257
mentions BAYLY and HARTHILL, and seems to fit your timeline.