FrankHarveyHiFi:
I've mentioned in another thread that Monitor Audio, whether it be the new RX, or older RS or GS, isn't suitable to be used up against a wall. Rear ported speakers use he wall to reinforce the bass, which is fine if the speaker is bass light, but generally they already tend to be bass heavy models already. Pushing them against the wall just exaggerates this issue.
The only way a rear ported speaker with a tendancy for a strng bass can work against a wall is if the wall is an extremely flexible stud/partition wall. This soaks up much of the bass, but still might not be enough.
Brands that generally fall into this category are Monitor Audio, Dynaudio, and B&W - all of which prefer breathing space for them to give a more even bass response.
To the OP, a sealed cabinet is the way to go. As there are very few of these on the market, the ATC models are the best place to start looking. If you did go for these, I would recommend adding a power amplifier at a later stage to i-amp to get the most from the SCM7/SCM11, which are the two that fall into your price point - which one you choose will be dependent on room size.
I wouldn't recommend Monitor Audio with an all Cyrus system, full stop. True, Dynos & B&W's need plenty of breathing space, but don't write off all rear ported speakers. I know that Epos work very well with Cyrus and close to the wall.
Why not try Dynaudio's and bung-up the ports?