Emily A permanently roofed al fresco will reduce some summer heat gain (although sitting out there may be uncomfortable) and will do the same for winter. From scanning the comments it appears that you are at a point where you can still may major changes; I cannot recommend strongly enough getting the orientation of your new home right, it will be warmer in winter, cooler in summer and be significantly cheaper (if not free) to run with some appropriately detailed insulation. I do understand the appeal of a floorplan that seems to be all you have aspired too but have seen many a case where people have later regretted those decisions. If you are unsure about the pros and cons of various floorplans then get a design professional (building designer/architect) to give you guidance on an hourly rates basis. good luck

Gum trees are provide a stunning canopy to any garden, but as with any large tree close to your home, you need to be mindful of its health and possible future limb failure. Sudden limb failure in Eucalypts is the result of periods of dry weather, impacts on a tree's root zone and subsequent moisture stress. I recommend creating a beautiful native garden in this area with groundcovers and grasses that are suited to the sunlight available. Make sure the area is properly mulched (organic mulch is best) and that you water the area during periods of hot weather. It's also worthwhile having an arborist look at the tree every 12 months of so to make sure it is still healthy.

love concrete aggregate and it look greats mixed with other surfaces (bordered with a brick can be very effective) but first test a few different mixes to include the various colour stones to complement all the different floor colours both inside and out and make sure all the aggregate flooring is completed together (or the mix of aggregate is prepared at the same time) to avoid patches of different mixes

Eltham is cold in winter so any heat/cooling help the environment can give you will be free and appreciated! I agree with living there for 12 months first. I thought, up stairs, to open up the study area as it will let light and sun into the whole open area there. I like the idea for the robes in the front bedroom (tho you have not said how many people will be living in the home) Down stairs: I agree with living/ dining on the north side might be more welcoming for everyday living and I would be adding more windows along this wall to aid the solar efficiency. Adding doors to the rear too from dining. getting the eave length right for winter sun and summer shade. Powder room/mud room great idea I would add a shower for pool, broken leg or other convenience!! Leave laundry where it is but arrange it better with no dead corners. Is it possible to build a walk in pantry under stairs: even if you have to add plaster to the arc of the stairs (and the robe above become a walk in?) it is a great opportunity! I like the idea of the open kitchen to dining, meals with tall storage under stairs or that side. I don't like the idea of knocking wall out family to entry but cavity slider 1 or 2 would be handy (Make sure of furniture placement b4 grabbing the sledge hammer!). The fire you are more likely to enjoy in evenings, it will only be efficient enough for that one room or heat becomes a draft up stairs. access thru sliders nice but close it off for intimacy & warmth too. Hope all this ramble helps too! Cheers Margot