Why don’t you use plan B, put the dining area in reception 2, the kitchen across the back, the shower where the utility is, the utility above the shower room (so to speak) and the guest room / play room in the little nub on the end. That way, your dining room is fully open to the kitchen for maximum light, the shower is accessible off a small hall, so not off the kitchen, the utility is off the kitchen and you’ve got a lovely light room in the space looking onto the garden that can be closed off is needed. Haven’t got a pen / paper to hand but hopefully you get my drift