I picked this miniature up second-hand yesterday with a batch of bits. I don't recognise him, and suspect he's from "after my time". I don't think he's Citadel/GW because of the lack of a name on the base and the shape of the shield stud. I could be wrong, though. He's fairly big - the Citadel beastman next to him is almost 40mm from hooves to crest, and he's about the same.
Thanks in advance for any pointers to his origin!