You mean the rumpus room? I don't think so, there's no obvious place to put a tv opposite a couch. I would make the lounge the home theatre, possibly closing it in on one side of the wall, and putting a door on the other, and take the wall out between the rumpus and the dining, assuming that's possible. Much more flexible floor plan, as you can choose to put a family room or a dining room closest to the kitchen.

how about some more storage, and the toilet on an outside wall for some fresh air for a start. also garage seems quite narrow, 2 cars 1.8w leaves about 1.8m divide by 3 leaves a 600mm gap between car and wall and car and car etc

3.2 X 5.4 is a good T V room but not my idea of a theatre room. I'd be looking at least 4.5m X 5.4 to have the theatre feel. Sadly it wouldn't fit with your plan sizes but I feel a theatre room needs length and width. Hope this helps.

It is probably a bit narrow for a theatre room. The area that will let it down is from a sound perspective. Placement of speakers is crucial to getting the effect of surround sound. Putting it very simply, too close together and the sound will blend in together. Too far apart and you will get a dead spot. If they're not angled appropriately you will get phasing issues which will cancel out certain sounds. For that depth of room, i would probably recommend about 4.5m wide.

On a slightly different not, i find the placement of the laundry rather odd. You will get the noise and vibrations from a washing machine/dryer in the two rooms that you probably least want it in. The other consideration you may want to look at is keeping the rooms that have plumbing on the same side of the house or at least as close together as practical. Keeps building costs down.

thanks @Vy this was one of the better home cinema guides I read :)