I can see you've got a good budget but think about energy saving because energy/water prices are going to rise over the years and being se you'll get hit first.
So, plumb the dishwasher (miele?) into the hot water supply because they only use 6-9 ltrs for most loads and gas is a cheaper way to heat water than electric. The washing machine can stay on cold, they use more cold than a dw would.
Grey water recycling system? It recycles water from the washing machine, dw, bath/shower etc to flush the loo.
If I was self building I'd want brick walls upstairs and insulation inbetween floors.
15mm thick underlay in carpeted areas, it's warm & quiet. Noisy houses grate on you after a while.
Draught proof, it's really basic stuff but silicone sealing inbetween the floor and skirting & the electric sockets boxes reduces the draughts which keeps you comfortable. You want ventilation where you want it, not where you don't.
Ask if the builders can insulate the pipes feeding the radiators, otherwise heat goes into dead spaces.
Hydronic plinth heaters, they blow air out but use the heat off the CH pipes and only cost 25watts to run. We have one in the kitchen and one in the bottom of the stairs.
Buy the most powerful kitchen hood you can find, you don't want kitchen smells spreading throughout the house.
My cousin in laws house has bathroom extractor fans that run 24/7 but are silent.
I'd love a wine fridge!.
Yy to water softener & quooker tap.
Triple glazed windows are a must, not only do they have a similar "U" value to a wall they are also quieter. What's not to like?.
There's an app called issu, it has loads of magazines on there. Usually a month behind but it's better than paying for them.