Greys can be tricky and "read" so very differently in one space to the next, depending on the light. Dulux Raku or Malay Grey may be worth a look for deep tones. Also, check out the colour atlas at the paint store as it will give a lot more choices then the display of sample cards or brochures. This will also tell you the Red, Green and Blue value (RGB). You'll want the blue value to be less then the red to get a warm grey.

Thanks for everyone's help. We have decided on Whisper White with standard decorator's white for the ceilings, as suggested by you and the painter. I also found this earlier post about white paint shades to be very helpful for others facing this dilemma! https://www.houzz.com.au/discussions/3019158/which-white-is-right

It was one of the colours the Dulux rep recommended. If you can, get sample pots and try them out. Best way to check your colours as photos don't always give a true reflection of the colour. Then you can have a look against your tiles and in different light.

What natural light do you get in the room/what orientation? i.e. is it a 'cold' or 'warm' room? If it's a colder room, I'd go with a grey with orange/red undertones to warm it up a bit, or if it's a warm room you could get away with a cooler grey, maybe green undertones to compliment the maroon. Or you could even try a green rather than grey. The Aerobus is a blueish grey so will be cooler. As others have said you would probably want a lighter tone than this for the walls (unless you're purposely going for a dark dramatic mood). 'Miller Mood' is a couple of shades up in the Colour Atlas. Get sample pots and paint a section on each wall, or paint a white bit of card and stick to the wall to see how the light is at different times of day.