The fortunes of war swung wildly in this battle, at times looking good for one side, then the other. The heroics of the Scots warband to block the road was critical as it held up the English reinforcements, The English had another infantry division unable to reach the field because the wagons were in the way. By the time the way was clear the Scots cavalry was in a position to destroy the wagons & the battle would be lost anyway. For a long time it looked all over with the English one bad dice roll from an Army Break Test, but they just kept on hanging on taking the Scots to the brink of breaking themselves before their cavalry could finish the battle.
While the Scots have won both times we have fought this scenario, it's far from unbalanced. Each time it took some good decisions & a bit of luck to win.