Juliefrontera is right - this floor plan needs a lot of work to bring it up to modern standards and you really should seek the help of a professional. I agree that there is a lot of space being wasted with hallways, and there is only one bathroom in the house. Also, you have a back bedroom that can only be accessed from the "lounge", which I assume is the living room? Usually, the living room is at the front of the house and the kitchen flows from that space, so my first change would be to knock out the walls between the front bedroom, lounge and back bedroom and re-create that whole space. Of course, then you are asking about moving o,imbuing, must consider whether there are load-bearing walls, etc. so, definitely hire someone who can help you with this. And good luck!

What did you end up going with? The plans look mighty complex.

Third vote for getting a professional involved, but i'll still offer my layman's suggestion given that you're just soliciting general ideas at this point. If it was my space, I'd switch the bathroom and the laundry room around, keeping just one of the walls currently enclosing the toilet. Its hard to estimate precise measurements from the drawing, so it may not be feasible, but here's what i mean

Is that a wall to the left of the machine? Or an appliance? I like "patrim's" ideas and would add if that is a wall, hang your crates there to stash your supplies in if you don't want to invest in cabinetry (or cant fit supplies under sink), this way you get the functionality but don't see them when you walk in the room (assuming you are entering from where you took picture). And hang a picture or something more decorative over the washer/ sink as this is where your eye will go. I'd also consider painting the walls a pretty color, to contrast with your wood trim and warm up the room a bit. I love the window, great light for a laundry room!