In my eyes consciousness is the bare awareness and perception is mainly how this awareness is colored. For example, one person might perceive radish to taste nice while another perceives it to be awful. Also we could wonder if we all perceive the color red in the same way, and things like that. Perception often tricks you into thinking things are one way while they are another way. Consciousness itself can't do this because it is below that level.
I think the MN43 quote is not that you can't understand some differences between perception and consciousness, but that you can't have one without the other. No painting without canvas, that sort of idea. If there was no noticeable difference there would be no reason for the Buddha to have separated the two.