In addition to this, other things to consider are:
1) Extending the benchtops in the kitchen a little, and adding a breakfast-bar overhang
2) Adding doors to the linen in the laundry
3) I would consider changing the shower screen in the main bathroom to a sliding one, otherwise it will knock the door (this happens in our house)
4) The WIR in the main bedroom is quite small. Usually it's best to have about 2m hanging space for each person. I would see what can be done to increase this. One option is to centre the ensuite door, shift the main bedroom door down, and then put built in cupboards either side of the ensuite door.
Thanks for your comments and suggestions Amilelka. I will certainly consider some of your suggestions especially the kitchen ones. I have an intention to add one built in cupboard on the wall separating the bath and the M/bedroom.
With the bulkhead I'm still wondering how they would remove it, considering there are no eaves.
To complicate matters, I am raising the ceiling to 31 course for the entry all the way through the family/dining and communal areas. Hopefully it can be done without much cost. I've just about hit my budget limit.