Help with boolean difference

Hi,Im trying to use half of the attached meshes to make an imprint on a surface (like a chocolate box). I struggle to get it to work though. Have tried Boolean Difference inh Meshmixer and Blender, but does only pruduce non working results.Thanks for your help!Martin

I selected the Queen component, then performed a plane cut and aligned the cutting plane to the monolith. On execution, I selected both components and performed Combine. The result is attached. There was one flag within Analysis>Inspector but selecting it for repair did not cause any apparent damage. Hope this helps.

Okay, that was WRONG. You're asking for the difference and I did a combine. Sheesh. I'll get back on it in the morning.

Now that I'm awake, I used Fusion 360 to import both meshes, used Mesh/Modify/Combine and created the attached file. It passes Meshmixer's Inspector.

Hope this is what you wanted. If not, let me know where the misunderstanding lies.