Thank you all for your comments. Well, it's been a few months since my original post and we have since finished putting up the retaining wall and planting the hedge. We decided to go ahead with Murrayas - planted about 34-40 cm apart. I gave them a good trim about a week after planting at the end of Autumn and another quick trim at the start of Spring. They have really filled out in warm weather and I think the gaps between individual plants should close by the start of winter. I'm really happy with the choice - the hedge looks glossy and lush and the sweet smell of Murraya flowers is just beautiful. We didn't do any underplanting, but I'm still thinking about putting in the dwarf agapanthus for the inside border. A couple of weeks ago we planted some Rhaphiolepis "Snow Maiden" and Rhoeo along one side of the retaining wall to provide a border for a footpath and I'm really happy how it turned out.

@Emma I, What you're suggesting is a pretty bold move and irrespective of whether you are permitted to do it in the end by your respective shire and other authorities, I can't stree enough that for all the money you are thinking of spending on this project and the lengths to which you are intending to go with removing windows, dig a huge hole for the pool etc... that you use some of your finances to employ an architect as suggested by EmileECLC to make sure that this massive transformation becomes everything you dream it will be!! You must be absolutely sure of regulations surrounding pools like mentioned by mazgardiner about not being able to directly enter a pool from the house for example. Hubby and I are building our own home and we decided to have an indoor pool. We were originally having a sliding door leading outside of the pool, only to find that we were not permitted to have this access from the pool outside and I expect it was the sliding door, as with mazgardiner that was the issue, as it would be far more difficult to make it a self closing and lockable door. Fortunately we had already decided to change the slider to an awning window instead and just as well. The access into the pool from inside the home is a hinged door with a self closing mechanism and has the handle positioned at 1.5m from the floor. Furthermore, we were told by the window manufacturers, that any glass near a pool area had to be safety glass by law, so your stacker doors or any other windows that form part of the new pool area, will need to be upgraded and be much more expensive just so you know, about double the cost of a standard window. Another safety feature with our awning windows was that the wind out chain could only open to a maximum of 100mm, again law, just like the bars in a safety fence. Our building inspector tried to tell us they would not be allowed and that we would have to have external bars fitted and have the windows permanently screwed shut but further contact with our state building commission deemed the 100mm gap to be safe and adequate. Don't just accept something that seems wrong, if need be, take it higher as we did and succeeded, so again another reason to have a professional helping you through the maze of regulations.

Nice @julie herbert i like how its formal without being overly formal. Here is a photo from yesterday as i was pulling out the yuccas. I just need to be able to get enough height so its visable above the hedge, or ill cut the hedge lower. It originally had a bird bath in this location but i had to remove it as it was too damaged. I think a water feature in this location and a square hedge in the other location with a chinese tallow in the center kind of like your water feature could work well. @Liz I haven't removed all of them i'll likely be keeping the ones closest to camera, just the very large weeping one was a nightmare to get around.

Your site is far too exposed for Maples. They are small trees that really need to be buffered from winds and too much sun by other plantings. They also need the soil constantly moist which will be nearly impossible on that slope. You really don't want to grow magnolias anywhere near the footings of a house. Have you seen how large a tree they are? Since you are in a temperate zone and like autumn foliage I can recommend a gingko tree. It will be right sized for your yard and give you that similar lighter than air look and autumn colour as maples but it's more hardy. Another option are silver birches. I would hedge the boundary for privacy and also to cut down winds to your garden which will dry out the grass and scorch it. With that slope you are going to need more rocks I think to prevent your topsoil from washing away in the first rain. It's really no use of us to provide you a list of random plants. What you need to do is put together a series of photo's of gardens you like the look of, then find plants to match that style. If you don't plan gardens then you end up with the ubiquitous suburban patch of grass and odd bushes look instead of a lovely garden.