This mount is illustrated in "The Vikings in England" (1981, pg 184) where it is described as being in the English Urnes style and as probably a box or book mount.

"The Urnes style flourished in Scandinavia from the mid-eleventh to the early twelfth century, being adopted in England at a similar, post-Conquest date (Wilson 1995, 217-8;Fuglesang 1998; Owen 2001, 205)." Kershaw (2011).