I have an idea for an approach that might work but don’t have the time right now to develop.
Basically project (Replace face) segments of the art onto the guard in a piece wise manner. You need to experiment with angle (20 degrees shown), number of steps, depth, etc. Hope this helps…
Thanks mate good idea that. I ended up creating a octagon inside the piece & extruded shapes from that to carve. It wasn’t the best idea as I was still using the translate/rotate to fine-tune some pieces.