Thank you - that makes sense if people are just quoting the unit costs and not allllllll the other components!
We went back to Howdens at lunch with our door sample of the lovely wooden door. The lovely wooden door is far darker and on comparing them the Fairford is a better shade. So we made a decision! Fairford it is.
Rather crap plan attached, we're moving the island left by about 100-200mm which will just about buy us enough space for a narrow dining table & benches on the right under the velux rooflights.
I think the quartz estimate was about £2.5k, just waiting on a firm quote for that. Should be able to get the straight run & island from one slab & hopefully just enough offcut for a small worktop on top of the washing machine (which is being moved to the current downstairs loo space).
I need to contact the LVT flooring guy my in-laws recommended regarding Karndean, but DH keeps flip-flopping about what to have so will try and pin him down to a decision on that first!
I have samples of some nice tiles for the splashback BUT I also found a couple of boxes of the gorgeous crackle glazed white tiles from our upstairs bathroom that I forgot we had, so if we have enough I might just use those...