Your Ground Floor
It's was hard to choose with so many possibilities and such a great house to work with. This one really needed to come to down to budget for my personal choice. I would say the layout you suggested (which is option one) would fulfill everything you need in the space. It has great flow between areas. I love the entrance through the back with the utility and boot room but also that a minimal extension is required, keeping much of the original feature of the house as well as keeping costs down.
If however, the budget is there and to improve the overall feeling of space in the house, I would go for options six. I love that you gain the downstairs feature suite (which could be as in option 5 if preferred but still gives you that flexible space). I like the open plan space using the better natural light coming in from both the front and back of house, the addition of the shower room and of course the casual seating area which is great for the kids whilst your in the kitchen or for entertaining guests. It has a real homely feel to it in both style and flow that will work perfectly with the house and your lifestyle.