Thank you so much for your advice MNetters! From your posts and links (including the Kitchen Lessons Learnt thread) I humbly present Version 1.0 of the "List of Kitchen Design Considerations"
It's a jumble of warnings, advice, ideas and personal preferences (sorry if I love your pet peev!) I’ll update anon with additional things I can think of (please add your wisdom too MN!) and hope to use it to plan a well-oiled machine of a kitchen!
Layout (straight from the mystery clever mumsnetter!)
Where you will put hot things out of the oven to check them?
Where will you put hot pans if you need to take them off the hob?
Where will you put your plates or serving dishes when dishing up a meal?
Where will you put your dirty stuff before you load the dishwasher or if you need to run two loads (eg after a large meal, so a load for pans / cooking stuff and a load for plates, glasses and cutlery etc)?
Where will you put the toaster or kettle?
Where will you use appliances that you don't keep out (eg blender, mixer, slow cooker etc?), will they be in the way of anything else such as where you dish up or where you put the food from the oven?
Where will you prepare food?
Can you fit people in doing different tasks, such as preparing a meal / cooking, making a hot drink, emptying the dishwasher etc without being in each other's way too much?
Can you empty the dishwasher without having to close the door to access a storage cupboard for lots of the items?
Think about where you are going to store everything - your everyday plates, granny's best china, cutlery, cooking utensils, herbs & spices etc, tin foil etc, bins, cups, glasses, bread, veg that doesn't need to be in the fridge, baking stuff, appliances that you don't want / need out all the time, roasting tins, the worlds largest turkey serving plate, wine, cooking alcohol, cook books, tea towels (in use and storage), kitchen paper, etc etc etc. everything needs a home, otherwise you will be cursing every time you need it or have to move it to reach something you use more often.
Lighting
Install plenty. Ensure good lighting in the food prep area.
Sockets
Get double the number you think you need, or a double socket at least every m along the wall, 20cm above the worktop.
Get a certified electrician to install, not the kitchen fitters.
Put some sockets inside cupboards for charging electronics or running small appliances.
Don’t have them too close to the corners or you won’t be able to reach.
Heating
Underfloor heating is mellow and lovely although limits the range of flooring.
Worktop
Find a beautiful, low maintenance worktop at a reasonable cost….
Flooring
Tiles can be difficult to keep clean and everything that lands on them seems to smash.
Wooden floor should be treated with yacht sealer to avoid staining and aid clean up.
Put floors down before the cabinets to enable moving of cabinet and keep wildlife out.
Food storage
Pull out larders are very useful; similarly a pantry cupboard. A walk in larder is the stuff of dreams.
Do measure the height of your typical food products (e.g. cereal boxes and bottled water).
Plan your spice storage.
General storage
Cabinets should be extended to the ceiling to avoid the smelly, sticky dust, although accepting that the tallest cupboards will never be used.
Write out every kitchen category on a post it note and plan where it will live.
Drawers are better than cupboards (in particular for under counter storage).
Plan to have a takeaway menus & batteries drawer.
Just say no to carousel cupboards.
Magnetic knife racks are recommended, although particularly by burglars.
Waste disposal
Plan with great care where your bins (waste, recycling) will be – freestanding, under the sink or in a cupboard. This is a topic of great debate.
Apparently bins directly on underfloor heating are smelly.
People quite like their Insinkerators. The safety of small animals is uncertain…
Sink
Have one wide sink, not two small.
Kitchen Tap
A mixer tap controlled by one handle is useful.
A mesh diffuser if a must or you will be splashed every time you run the tap.
Some people love the boiling water taps although they seem a bit scary.
A water softener saves scrubbing.
Dishwasher(s)
Should be close to the sink, but must be openable without vacating the sink station & without impeding opening of other drawers.
Some people recommend having two.
Oven(s)
Don’t have to be in the same place as the hob.
Higher up ovens may be easier to use.
Don’t forget the microwave.
Hob/extractor hood
Hob: induction all the way apparently.
Get an extractor that actually extracts steam rather than redistributing it around the kitchen.
Make sure it isn’t installed too low so you don’t bang your head on it daily
Fridge/freezer
Check the internal volume – this varies hugely
Fridge doors need to open beyond 90 degrees for you to pull out drawers.
Towels
Plan where the following will live: tea towels, hand towels, kitchen towel
Organisational HQ
Have a space for the family calendar, recipe books, papers and all the rest that ends up in the kitchen.