stuck on the cloak of molten metal broken leg gully quest battle

[McBrill]

Im trying to go through all the quest battles but this one keeps kicking my ass, How do i beat theis? benn setting up with outriders in vanguard to harras the enemy that arrives on one side and the rest of my cav on the other side with my infanty in the middle with three spear in reserve to stop their spiders that circle round to take out my artillary. my outriders get caught by their fast spiders and boars, my anti infantry cav cant get round to attack the enemy archers, as they keeps getting caught by the enemies cavalry or spearsin the confined space of the gully. Help please.

[Wyvern]

I did it after already beating the campaign when farming for achievments but my comp was balthazar+warrior priest, 6 swords, 2 halberds, 4 crossbows, 2 tanks, 2 hellblasters(cuz they look awesome, actual usefulness meh) and 2 cannons. Just bunkered down on one end and let them come to me, pestered them with balthazar(on a pegasus) to bait them in. Crushed the arachnarok spider with mass arty before they got anywhere near me. Used the steam tanks to absorb their main attack while my infantry+firepower mopped up the wannabe flankers, then threw swordsmen in to back them up. With Balthazar+priest buffs theyre really tanky and eat damage while your crossbows tear the enemy up. If you don't have steam tanks, I assume something like greatswords might be able to hold okish. Demigryphs with halberds would prolly do a better job than normal halberds vs the enemy cav, and trading hellblasters for a more functional arty could be good too.