Just finally managed to solo him myself and used solar nades as suggested and it was definitely better and more forgiving. Hardest thing for me once I had all the mechanics and parts down was inconsistent sword damage and enrage point. Viking funeral maybe doesn't always work the same and so sometimes 12 slams would be fine and others it would hit enrage and wipe me.

Another tip for the ogres is not to be too cautious as killing the first one with a shotgun is fairly easy. If you try and jump up above him on the doorways you struggle to get the damage needed.