I think you can get a bit bogged down in all the detail, right down to worktop and flooring and door handles. These can be changed, relatively easily. The placement/ size of sink and cooker/ units/ free standing fridge freezer or built-in, is a lot harder to change. My recommendations would be to start from the big stuff and then work down to the small stuff. Even worktop can be changed in a couple of years.
a. Have sink on the same worktop line as the cooker/ chopping board, even if it is round a corner. I have my sink opposite my cooker and the amount of floor drips (which then converts to dirt) is amazing. Eg. wash veg and put in saucepan - drip, drip, drip. Wash fruit/ veg and put on chopping board - drip, drip, drip (my chopping board is next to cooker, which makes sense). Wash hands and go back to cooker, drip, drip, drip. I never realised this was an issue as my last cooker was round a corner from the sink and I just didn't have the floor dirt issue as much.
b. Get a free standing fridge/ freezer. Built-in is rubbish. I regret my built in.
c. Love my bin under sink and my extra large sink which is incredibily useful as I don't have a separate utility room. Or perhaps you want 2 sinks or a 1.5 sink. Don't regret your sink choice!
d. Do you really want a range cooker (6 hob) or not? I considered it for ages as there was room for 6, but decided I wouldn't really need it. I went for 4 hobs and it is perfectly adequate.
e. Spend money on appliances not cupboards
f. Ikea is awesome. A lot cheaper for the kind of cool stuff you get - like drawers for pans etc.
g. The pull out drawers are amazing. I have all drawers, either wire racks in cupboards or tall pull outs, or large drawers for pots and pans. No more getting all the stuff at the front out, in order to reach the back.