I have written a 300 page book on the history of the Had(d)ath family including the Richard you refer to. I will be glad to share with you, but can't do so until I return home in September after a four month tour of Canada (I am replying to you from an Internet cafe in New Brunswick). Please drop me a line to firstname.lastname@example.org
in September letting me know your connection to Richard and what you would like to know, and I will take it from there.
usually in Salmon Arm, British Columbia, Canada