Australia has nice examples of painted and rendered Art Deco homes. If it was a different kind of brick I would say keep it, but I think painting/rendering would really brighten the place. I love the windows. Although all pics here don't exactly match your style, they are all of that era. As mentioned in above comments, there are mix of landscaping styles that suit from conifer/gravel/grass to cottage rose garden to an Australian native garden. Do what reflects you and how much time you have for your garden.

We recently updated an apartment to sell and got great feedback from the buyers on the paint - Dulux 1/4 Lexicon low sheen on walls and Vivid White high gloss on doors, picture rails and trims.

what a great looking house, love the windows and bricks ...i would maintain the existing mid century look of the house by first repairing any damage and cleaning all the concrete, keep the varnished eaves, paint windows and trim white again and repaint the handrails in a very dark brown or grey and maybe a a bright colour like deep turquoise or acid green for the front door ..it would be so much better to embrace the original style of the house instead of attempting to "modernise" it too much...it's difficult to tell from the photos but with a flat roof the fascia might also look good in the same dark colour as the handrails

I look at the first picture , and the most noticeable thing ( in a good way ) is the letterbox -- its an offwhite by the looks of it . So I'd do all the trim in that , and it even works with the roof ( sort of ) . The garage door is okay as it is -- the lighter tones elsewhere will balance that IMO . Ideally , I'd look at changing the garage door to a cedar timber at some stage -- again that would work with the roof , bricks , trim , etc . Probably just me , but I'm with you about going darker -- it may look 'dingy' , but none of them seem a fit with the roof IMO . Even something like surfmist ( off-white with a slight blue tinge ) doesn't gel in my mind . If you had the budget , and did want to look more modern , THEN maybe go a charcoal like monument , BUT with the cedar ( or cedar stained ) garage door , and 15 or so 40x40 battens , again cedar stained , basically the length of the 3 right side poles , so there's still that 2 metres or so in the middle that is 'open' . The cedar door on the left , and battens on the right , will visually look reasonably balanced and modern , without being too symetrical . The downside is it will cut down the light a bit , so depends if thats worth more than looking modern .