As the Vikings are leaving for France, Bjorn has a ring on his left hand ring finger. When Bjorn looks towards another boat a moment later, he is holding the ring in his left hand with his thumb and forefinger.
At approx. 24:34, when King Ecbert dispatches Aethelwulf and Alfred on a pilgrimage to Rome, as they leave the gates a modern building can be seen, to the left of Judith's shoulder, complete with a modern style roof, modern style chimneys &, what appears to be, a TV aerial.