Possible Clues:

• Scandinavian starts to seek employment in Opera North
• Invader overrunning south-east, or one attacking north-east?
• An old Scandinavian, though having no right, calls back
• Viking invader of England holding Kent area
• Raider of the 10th century
• A Viking
• None could make them invaders with 16 down
• Viking regularly trusted to invade an island?
• One invader or another seen around the Hastings region
• As Fortinbras calls boy from the south