I do not know if this is of any help but in the past few days there has been an article in the Daily Mirror about a Roy Blackmore from North Devon who has traced his family tree back to Domesday.If you go to this website there is information about the family being connected to the Courtenay family - this may be your line so may be worth a look.The website address is: http://www.royblackmore.co.ukhttp://www.royblackmore.co.uk
My family school is in North Devon, boys in the family have gone there for four generations - West Buckland School and the four houses at the school are Courtenay, Fortescue, Brereton and Grenville.
Unfortunately, I am having so much trouble in trying to link my James Blackmore b. 1790 Newport, Gloucestershire into the North Devon family but I am sure it will happen at some time.However, having spent 30 years trying to get information about James but being continually told the records were lost in WWII bomb damage I am beginning to think the brick wall will remain in place.
I hope this Roy Blackmore site can help. Maybe you have come across him already.
Regards Gail St John-Moore
P.S.The Moore family crest I understand is based on a Moore marrying into the Blackmore family in the 14th Century.