A few more recommendations for the King Arthur - Harold section:
Non-fiction on King Arthur:
The Reign of Arthur: From History to Legend, by Christopher Gidlow. Clear, readable, balanced survey of the evidence for a historical King Arthur and subsequent development into legend. Review here for more information:
http://www.carlanayland.org/reviews/reign_arthur.htm
For the mid-sixth century, I can recommend
Born of the Sun, by Joan Wolf, a novel about Ceawlin of Wessex.
For the seventh century - between
Storyteller by GR Grove and
An Involuntary King by Nan Hawthorne in the King Arthur to Harold section of your list - I highly recommend Kathleen Herbert's three novels set in Cumbria and Northumbria:
Bride of the Spear (first published with the title
Lady of the Fountain). Late sixth century, covers King Urien of Rheged, his son King Owain of Rheged, and Princess Taniu of Lothian.
Queen of the Lightning. Early-mid seventh century, 630s-640s, covers King Oswald and King Oswy of Northumbria, King Penda of Mercia and Queen Rhianmellt of Northumbria (Princess Rhianmellt of Rheged). ('Queen of the Lightning' is an approximate translation of the name 'Rhianmellt').
Ghost in the Sunlight. Mid-seventh century, 650s, covers King Oswy of Northumbria, King Penda of Mercia and his son Peada, and Queen Alchflaed of Mercia (Princess Alchflaed of Northumbria).
These are unfortunately out of print at the moment, but there are second-hand copies available on Amazon. They are sometimes billed as 'The Cumbrian Trilogy', though I would say the first one (
Bride of the Spear) is a stand-alone and the other two form a pair. I like these very much; they all have a strong plot, well-rounded characters, a firm sense of historical time and place, and are beautifully written with a dry sense of humour.
If you don't mind my mentioning it, there's my own novel
Paths of Exile, about Eadwine (Edwin) of Northumbria, set in the early seventh century, 605-606. It was Book of the Month here in April last year; I think this is a link to the thread if interested:
http://www.historicalfictiononline.com/ ... php?t=3217
For King Alfred, I can also highly recommend Joan Wolf's novel
The Edge of Light. It will give you a distinctly different take on King Alfred from Bernard Cornwell's Uhtred series.