have you considered not having a separate laundry, why do washing machines deserve their own rooms? Combine it with the bathroom, unsure what is happening outside so can't comment on how it would impact the flow around the building.

Based on the plans you provided I would go with number 2 (top row - right) with everything on the right hand side, so you walk in the door and the room looks spacious and you are not looking directly at a toilet from your hallway. All the plumbing runs along one wall and that is always the cheapest option and you can have a heated towel rail or similar running along the wall next to the entry. If it is possible I would rehang the door so it opens to the right not the left and then I would swap the toilet and basin so the toilet is tucked behind the door (for a little more privacy) and the vanities will be next to the shower. Good Luck.

My suggestion would be to run a large shower along the wall where you currently have the vanity with a single glass panel ending so that you can enter the shower where the timber bench stool is . The vanity on the wall opposite the door with a row of recessed mirrored shaving cabinets above. You don't plan on a bath but what about a toilet. None of my etchings are to size this is just for possible ideas

@oklouise thanks for measurement suggestions, good starting point with so many choices available. About the bath, we thought just a freestanding, or back to wall bath, would take less space compared to drop in bath. But it something worth considering with the suggested layout. Also, the bathroom entry door would be sliding cavity if that helps. @differentways thanks for a suggestion that we haven't really thought about. We have considered a smaller Japanese style deep bath, but obviously this would not be practical for kids. Just to make sure I understand your concept, you are suggesting a purpose built bath which will be about 2570mm (including the ledge), husband thinks this is very generous :). My husband and I can't find a photo of something similar, do you have a link? Are you suggesting the sides of the bath to be a lower height compared to standard bath? I like the idea of a ledge, would definitely make bathing kids easier. About the position of the ensuite, do you mean placing it outside the bedroom area so it can be accessed by others? We have discussed this, still part of ongoing discussion. If need to we just have to move the bedroom entrance door. I have attached a google earth view.