I know about the equilateral triangle stuff, it is mentioned in the manual, these speakers are actually nearly creating that setup from their perspective, at the moment the tweeters are around 5cm to around 10cm lower than exactly at my ear level. So I think I only need to move it off my desk, is putting something higher under these speakers good enough as that as far as I can go with my desk space?
I would say yes. And if you don't need them to go all that high, you could use bricks. They are inexpensive. I bought 4 bricks for like a dollar and some change, and spray painted them black.