I'd say there's not a lot you can do with the garage, overall height limits and ceiling height to garage perhaps? Limited info and unfamiliar with site, etc. so just really guessing here. The stairs however could be changed as could the balcony, etc. Can't see issues here why it can't be amended to suit your requirements. You never mentioned the issues with the designer but perhaps stay with them as redesigning through another may not be ideal either! Some won't touch another designer's work and will start from scratch. Give them another chance to explain why it is all done this way. Allow them the opportunity to amend it and depending on your council, use a SECTION 96 if possible. Council will soon let you know if they can accept it. Remember they've been submitted so I'd have to presume you were happy with them beforehand. Clients changing their mind or have difficulty making decisions happens regularly as its all quite new to them. I too have had clients that love the plan's, get submitted then decide that want to change something that has been there from the beginning.... Windows and doors are usually what my clients change. Frustrating for client and equally if not more so for the designer as it affects the whole plan set and documentation in many cases. I do know many designers will railroad their clients into decisions based on their own visions but this is never a good thing. It's a collaboration between client, designer, council, engineer, builder, etc. and sometimes a bit of compromise by all parties.

If you are in New Zealand, I have often found great lights (and a big range) at Lighting Plus. When I was putting my house on the market I put three of these: http://www.lightingplus.co.nz/lighting/pendants/contemporary/jaga-bcopal-1light-pendant.html over my kitchen benchtop, and they looked just gorgeous. So gorgeous in fact, that I have already bought three new ones in advance for when I upgrade the kitchen lighting in my new house. They also have these : http://www.lightingplus.co.nz/lighting/pendants/contemporary/hudson25-whitegold-1lt-pendant.html or these: http://www.lightingplus.co.nz/lighting/pendants/contemporary/trumpet35-pendant-blackgold.html  if you like the look of the internal gold under the shade. There are also others similar. I have also found some great lights at : http://www.edenlighting.co.nz/collections/pendant-lights . All of these are very affordable. However if you want to go really high end, and you like NZ timber lights, you can't go past : https://www.davidtrubridge.com/collection/lighting/  Just my 2c. Enjoy.

Where are you located? I have seen these at cerdomus tiles in Richmond and Moorabbin tiles in Moorabbin if you are in Victoria.

Thank you everyone for your great comments. There were design ideas I had never thought of and really valued like the floating shelf, a mural and larger cushions and changing the colour of the lamp shade. Attached is the latest room version. I have moved paintings around. I do love this aboriginal painting, I am not sure if it is a little small but I'd really like it above the couch so perhaps another complimentary painting beside it? Or do you think it works ok? I think I can pretty much choose any colour from the painting for cushions and to brighten up the space - was thinking brighter and larger like suggested above by littlethommo2 and littlethommo2 . I still think I have balance/scale to work on - thank you Paul Di Stefano Design and littlethommo2 . I can move the cupboard at the end of the couch with the plant on it and place something taller here ? Any further ideas are really appreciated. Thank you all !