Very interesting.

I'd definitely leave the brick and the roof, it looks like a good, solid and classic house a and the front door would come up beautifully in a smarter colour. I'd paint your front door, gutters and garage door Dulux Monument and it would look fantastic, particularly with your brick and roof couloirs and that lovely sandstone. Then the gables in the same sandy colour as your posts, though if it's too yellow-creamy you could use a warm grey taupe like Dulux Dieskau. Replace the coach lights with a sleeker but still classic version like Beacon's Southhampton and an additional pair either side of the front door. Replace the urns with say 3 simple tubular pots of varying heights on the left side with some interesting crassula and rounded Japanese box. Trim your hedge right down and thin out to shoulder height. Not sure if you can replace the finials on your fence as this Victorian style doesn't suit your house and is a bit dated. Then rip out any ratty looking plants (poor roses always look ratty!) and replace with plants that are ideal for the aspect - if they're in the shade only put in clients that in part shade even magnolia little gem is versatile. Otherwise a lovely sweet viburnum will add softness and bright foliage. Plant mondo grass in the tall pot and remove the pew bench and rectangular planters and get a new small batch of fresh pebbles for between the square pavers. You could even put an interesting bench (or that pew) along the wall on the right of the front door, style it up with a couple of outdoor cushions (KMART even have some smart stripe ones). and finally get the roof cleaned but otherwise leave it! it's a great house, it won't take much to make it look really fresh and stylish.

For low maintenance in such a variable climate while preserving light access I think I'd go for some kind of a translucent decorative screen, with maybe just a few potted plants to provide some greenery. If they're not planted in the ground you'll have to be even more careful to ensure they get enough water. Or, thinking further, I've seen Chinese star jasmine used in challenging commercial locations, including as a screen around a cafe's outdoor area, it looks amazing and appears to be very hardy and copes with a temperature range similar to yours. Two drawbacks though, some people dislike the smell and it needs pruning so not low maintenance. It's difficult finding something that ticks all the boxes.

I love Julie's ideas of succulents , especially the pics with several different ones in the same pot . As far as the grey , I wouldn't -- you look like you like colour and excitement , so I'd go yellow on the pots -- a similar or slightly brighter shade then the cushion on the couch or chair to the left . It would tie it all in , and make that lovely mat look more like a feature too IMO . Without knowing 'the bigger picture' ( what else is 'happening' around that wall ) , just what I see I'd be inclined to add a light either side of the door too -- stick to the same shade as the joinery ( personally , I'd go for a 'clean rustic; style with say 15 squares each side ) , or if brave ( and assuming the guttering etc is probably a similar charcoal as your door joinery ? ) , go for the same yellow as your pots -- add a Wow !