Suffice to say it's all gone back now. Too harsh in this room, but also the Arcam didn't have enough power to drive the Dynaudios. This was just in stereo mode. The Dynaudios are 4 ohms however. It just sounded harsh and strained. The detail was there. Plugging them back into the Marantz was a lot better but overall I was still unimpressed with them.
So they're back. I'm borrowing the Spendor S9s next week when I get back.
Unless I just order the Tannoy Sensys 2s. Hmm.