Harry, in a recent edition of Wargames Illustrated, which for some inexplicable reason I can't find anywhere
. Until about a month ago we were using it every week.... anyway I digress....
There's an article called Landwasters and Raven Feeders that features a LR variation for the Early Medieval period written by the author Dan Mersey.
If I were you I'd get in touch with WI and ask if that edition is available as a hard copy or a PDF.
Hope that helps?
Darrell.