Thank you Jonathan for your thoughts. We have worked with an architect to plan the house. The kitchen at the moment is an the first floor but it means we feel we live in a flat with little access to the garden. It is always an intention to spend time outside, especially meal times...it just never happens when everything has to be carried down to the outdoor. Interesting to have other perceptions. I will look closely at you living room layout suggestion though, hadn't thought of the layout you suggested. This would be more L shaped as the plan suggests. We can move doors, tv points and the fireplace could perhaps be evened up on the wall.

It’s not true to say it is always more cost effective to extend than convert a loft. It is also not true to say that loft conversions can’t be equally nice and three storey living has privacy advantages too. If your extension to the side was going to replace an existing garage with another garage with better foundations and a room above then this extension may well cost £30,000 (which may well be the same cost as adding a room to the attic). My plan would also not require the first floor to be extended over the new ground floor extension to the rear, which in turn would allow roof lights for downstairs and not first floor extending to the rear also makes a likely £7k cost saving. Furthermore an attic room may be squarer and easier to furnish than the narrow space to the side of the house. Lastly I find it hard to believe that a three bedroomed house would be worth more than a four bedroomed one but your local estate agents are the experts.

Lots of people use their utility to store extra things that don’t fit into the kitchen. Alternatively they have big dogs that they want to keep in the utility or use it as an entrance to the house and therefore a storage space for coats and shoes. I think if you are going to pinch some room off the garage I would make the utility room accessible through the hall (where you have planned coat storage) and make the kitchen bigger instead. I suspect this means you will have to plan around a pillar but I don’t see that being a problem.

I just screenshot and save as a picture, can be drawn on then. I find that removing the existing room labels and defining features ( like kitchen cupboards) helps to visualise how the light comes in and the possible flow of people. Jonathan's design makes a better flow to a back door, rather than going through a living room or through the kitchen to the garden room.