I use RFC modded original Eatons in a 4.5 x 3.5m room, firing down with more than a metre behind them. This makes the set-up somewhere in between near and mid-field. For me this has the benefits of near field, but with just enough bass to get some impact. I get far better scale than I would with mini-monitors, but just as good imaging. It's a good compromise for my modest room. With your 5 x 4m room I suspect Cheviots would work well, but it all depends on layout and placement. If you've already covered this, apologies for not reading the thread thoroughly, but perhaps say a little about whether you are firing down or across, how much room you have to bring them into the room etc.
Unfortunately I'm also skeptical about the Eatons with Naim amps, but perhaps with the legacy Eatons it might work ok. I heard mine with a Supernait briefly and didn't like it, but that was before I had essential mods done. The original Eatons are very studio-like in their FR balance and really need some attention to a notch between 3-4Khz. So it might have been that this was the worst possible match with Naim, which I think tend to add a little spice in the presence region. From what I've read about the Legacy Eatons, and the graphs I've seen, they seem to be a little subdued in that region, IIRC.