A grey colour with a green undertone could work nicely... this way working with the green fencing and trims. sample pots are definitely a must so you can play with strength of grey and ensure correct undertone. If budget allows vertical cladding could transform the space further and create visual height...

I don’t know whether you have done your painting or not but with your dark furniture and existing windows I would paint walls light warm grey and 150% strength same grey colour on the architrave .something different and grey , yellow and brown look good together.

There are lots of paint manufacturers apart from Dulux, and hundreds of whites that it could be. Unfortunately the natural light in the photo, the type of camera, any photo editing, and the adjustments on your computer screen make it impossible for anybody to say with any accuracy what the colour may be. The only way to find the right white is to get samples and make your own judgement on site. I always think that Perth light seems stonger and brighter than Sydney light - possibly due to Sydney's airborne pollution in the inner city? There are lots of online resources by various paint manufacturers about choosing the right white, but don't make selections from an online digital image as it won't be accurate. Best of luck, Dr Retro of Dr Retro House Calls

The flooring is such a big component of a space you really need to consider it as part of the whole look you’re aiming for. I would say that generally for practically the carpet would be darker than the walls.