I love your idea of extending, but understand your concerns re over-capitalisation. I think your budget will need to reflect how long you plan to stay in the house, and whether you consider the enhancements to your lifestyle as valuable an investment as the actual financial cost vs possible capital gain. Have you thought of getting in a real estate agent to discuss what effect any potential extensions or changes will have on the value of the property? I agree with MB above that the laundry is under-utilised space, and using the entry space would also be a very cost-effective solution. A way to really modernise the home with less expense than a large extension and new ensuite bathroom would be to close off the door between the existing bathroom and toilet and add a toilet to what would now be the master ensuite. The laundry and current toilet could become the family bathroom, and the kitchen could be extended very slightly by pushing out the exterior wall to create a scullery with back door, which could be closed off from the kitchen with a cavity slider. If you pushed out the laundry/bathroom wall to match, you could add a bath, too. Best of luck.

Thanks guys, I appreciate your help! I tell you what, it goes to show how important photography is, I looked at the Parisi website, although the basins may be nice they do not 'sell' themselves like Omvivo does with their photographs.

if each hand basin is 500mm and the counter is 1800 there'll be 800mm left to be divided into three portions...perhaps 250 on each end and 300 in the middle will give a symmetrical feel anything else will be skimpy but also consider the depth (front to back space) and given the option i would opt for a deeper counter for extra space along the back...50 to 100mm extra depth could be very useful

our plumber correctly installed our wall mounted spouts over the centre of the basin ie water directed to the plug hole but make sure that the basin is mounted forward of the vanity and spout is shorter rather than longer as the water can spurt forward if turned on too hard by unsuspecting guests