Did you pick a style yet? I like louvres but that may not be the look you are going for...

I want some decorative, ornamental only, window shutters for either side of three windows. Anyone know where in Melbourne might I purchase them

Between mid grey and white. Mid grey would blend better with your cream patio roof and supports. If you choose white, you will have three different colours externally.

Is that a photoshopped pic of your place , or just a similar place ? There are too many styles trying to happen there IMO , not only the windows , and like oklouise says , somethings don't quite look right . I'd do bars ( frames ) about 200mm from the top of the two upstairs sets of windows , to match the downstairs style . Unlike ok lou , I don't like louvres -- they are drafty and don't really achieve much IMO -- a kid can put their hand and/or toys and/or your valuables out there , my personal preference is top-hinged with a folding stay at the sides , so they open 150-200mm but no further -- no-one can climb or fall in or out , can stay open overnight if warm , etc . I don't particularly like the upstairs balcony and gable , but I'm not keen on the entrance door treatment either , and without knowing what it looks like now , I may be tempted to replicate the 'double square' look of upstairs , downstairs too -- make it all the same theme . I'd keep the garage in the off-white , because if you look at the right side , both downstairs and upstairs look a bit boring IMO , with that flat dark finish -- the garage door done the same would add to the slab look . And while I'm being picky -- I personally think the black or extremely dark grey is too dark -- toned back just a bit would be better IMO -- you don't want it to look obviously grey , but a nice charcoal IMO . And finally -- the column bases look 'dirty' -- imagine how they would look in a gloss black tile on the top and also the 'skirtings' ( or a gloss black paint at a pinch ) ; with white gloss tiles where you have a light grey ( or , again , maybe the same paint as your other trim , but $5k of tiling would really add to those ) -- I think that would work with your black , or even a charcoal , 'main' colour . Anyway , just suggestions , and purely my viewpoint -- it's quite a nice but still simple design , just a couple of small things that would bug me if it was my place .