Looks like a mott and bailey.
It does. While that method of fort construction is attributed to the Normans (and that site shown above might be of that date, guess they’ll find out and tell us), an earthen wall called Wat’s Dyke was thought to have been in response to the Offa’s Dyke, constructed along the border of Mercia and Wales. When someone actually did the work and got good dates, it was found to be at least three hundred years earlier, iow, may have inspired Offa’s Dyke. For that matter, given that the Wansdyke is of unknown post-Roman origin, perhaps Offa’s Dyke (or good-sized chunks of it) is older and not Offa’s work at all. :’)