I think plan2 looks/works best but i'd suggest a few changes. For the tower run, having only a 20mm filler is to tight and doors open more than 90 degrees so they'll be rubbing at the freezer end, i'd suggest changing the 600 and 800 larders to a 1200 breakfast style larder, having drawers and worktop inside, shelved above and power for toaster etc, the doors can be pocket style so they open then slide down the sides out of the way when in use, make the wall nib a bit wider by about 100mm so you have 50-70mm fillers at each end, probably bring the towers forward (or make them extra deep) and this would allow for the pocket doors to slide away more. Depending on ceiling height you could have extra tall towers or top boxes on top and then infill about 50-100mm up to the ceiling. Also check the height of the appliances as in the pics it looks to high, i'd have a 450 frontal with pan drawer and internal drawer instead. On the opposite wall as long as all the 800 drawer units end past the window is good, window sill same as worktop possibly, (either end the run before or after the window) lose the 400 open unit in front of the wall nib and have a door (door could be made to look like 2 drawer fronts to match) on this as it will be just a dust trap, in the 1000 drawer units i'd suggest having internal drawers for utensils etc, the corner unit is good especially with the fly moon pull out as they're great (in my opinion) and as the corner post is made on site its gives the fitter more flexibility in positioning the units as its not a fixed corner. The sink run is fine but i wouldn't suggest opening a d/washer door to let the steam out as it can damage the surrounding doors, cabinets, decor panels and even worktops (thread on mumsnet where steam has damaged granite worktops). For the island if a 500 bin is big enough then fine but you might find a 600 pull out is better as its usually a 4 bin unit, possibly change the 1000 1+2 so its a 2 pan with internal drawer and then on the other side i'd have 2x 800 which would look more symetrical. For wall units its up to you, but if its an electric hob (especially induction) the extractor should be wider than the hob and if this area is going to be a main prep area than having wall units you can add extra lighting.

Hi Jemma, I think you have a number of different options but fist of all, do you know how long your garden is? and what size extension you want to add? How much garden space are you willing to lose? You have a great space which gives lots of options for re-confirguring the layout. You could opt to square off the back of the house and re-configure the current playroom/kitchen/dining room space. This would keep your living room and you'd have a good size utility by converting the store room. I would consider how you feel about open-plan living. Do you want any additional separate areas? What do you want to achieve out of the space, in terms of family ilfe/use etc. All these types of questions will help get you to a floor plan that suits your lifestyle.

I agree with rinked - and this was pretty much what I suggested. Since it looks relatively straightforward to accommodate both utility and loo, I'd be inclined to go for both. Even if you've not had a utility before, having laundry done in a separate little room (doesn't have to be huge) will make an unbelievable difference to the noise levels in the kitchen - and other rooms, as you'll have a largely open plan downstairs. Otherwise, use that little space for a study/ reading nook. If you have pets, their equipment and beds can go there. Lots of options.

You are mistaken. The alternative plan delivers a rear extension that intrudes into the garden no more than the conservatory does. It delivers a much better kitchen than in the original house plan. It delivers a second living space without forgoing the cloakroom. Because garages tend to have different floor levels than the main house and a lower ceiling it’s not always possible to make them into a good room and personally I think it’s a horrible idea to build the biggest room in the house to have a view of the drive. So consider reposting your dilemma to include a drawn plan of your vision and I’m sure Houzz contributors with give you thoughtful feedback.