@kazzh Adding a wall as suggested by HU won't allow for the intention of an open plan with the living room as and adding a wall by the current opening will remove a lot of afternoon light from the living room. Adding the laundry to the pantry is certainly possible, it's an idea that has been considered, but we didn't know a) how possible it was to create a new waste pipe and where to run to, possibly the bathroom next door. b) how to position the pantry area to consider a reduced length of waste pipe to avoid a mass of disruption of other units ie cutting holes in them. Moving the patio door isn't impossible, as we can just brick up the current and add a window, then add a patio door to the extension. Thank you so much so far!

We just repainted some doors in a rustoleum kitchen cupboard paint which is a darker colour but it was painted on with a short hair roller and you can't tell its been painted by hand ie so they might not use a brush as such but still a roller would be classed as hand painted vs spray painted (if that makes sense). Nightmare re the scratches though!  I would have expected them to send new units/doors to replace the ones you have now and then the old ones get sent back once the new ones are ready. That's what happened with our old kitchen ie the company we bought off got the manufacturer to send new ones as they had someone come and inspect them and agreed that they hadn't been prepped properly as the paint came off the edges. That way we weren't left without kitchen doors for months!

Slide and pivot is a neater version of a bifold. Each pane is independent of the other and when you open the first like a door the others slide up to it and then turn outwards. they have much slimmer mullions than bifolds and give you more glass. I have been put off by the very mixed reviews on after sales service from some brands but they do look fantastic.

One option could be to make the sitting room bigger, than you have drawn, to fit a large sofa and creat a corridor behind the stairs with cloaks cupboard, then the kitchen on the left with island peninsular facing the garden and the extensions forming the dining/seating areas