Thanks for the clear steps. We are checking how the Thorn Remover is meant to work at the castle wall for Over the Castle Walls (4) and fixing it so using it there completes the quest. I'll post here when it is live with exactly where to stand.

Fixed and live (refresh the game). The Thorn Remover only worked at one spot by the castle door, not at the thorny wall where the quest sends you, and it failed silently, so the Secretary of Magic never accepted the quest. To finish Over the Castle Walls (4): go to the Castle Wall Edge with the thorny vines, stand right at the thorns on the right side and double-click the Thorn Remover. You'll see "You have used the Thorn Remover to clear the path." Then talk to the Secretary of Magic to turn it in. If you're too far away it now tells you to get closer instead of doing nothing. The castle door also takes you to the thorny wall until this step is done.