Thanks for the replies, this is very useful!!
Just to clarify, you'd recommend going with four CDT-5800 as Atmos speakers in the ceiling, but for the fronts, centre, surrounds and rear surround go with floorstanding / bookshelf style units?
It sounds like a false wall and an acoustically transparent screen would be best then, as it gives me some room for the bigger speakers at the front.
Someone else recommended I consider the THX-6000-LCR. I have no idea if they're a big upgrade over the RF-7 II and RC-64 II or not?
Unless I'm understanding Atmos wrong (please let me know if I am), the RS-62 II firing in two directions (180 degree coverage apparently) isn't ideal for Atmos?