Do the walls need replastered or just skimmed?
any problems in the room that need fixing before installing a new kitchen?
I would contact a few kitchen places first, have them measure up or take your measurements in and get a few ideas for the floor plan and get quotes
once your floor plan is set in stone then get a copy from whomever you’re buying the kitchen from , rip out old kitchen and flooring , check your sub floor to see if it needs anything done to it, ie any repairs or levelling, get someone in to do the plumbing and electrics if stuff needs done before plastering or maybe the shop have their own contractors who can do it , then depending on your cabinet style It maybe easier to put the new floor in before the kitchen , it will cost more for the flooring but you’ll save on a bit of labour as the installer won’t have to keep cutting around units etc , after that get the kitchen fitted, most places will have fitters they contract to install the kitchen or you could hire your own but if you let the shop sort it then everything is their problem if things go wrong. you may need the electrician and plumber back to 2nd fix and install some appliances but that will depend on what the fitter is qualified to do.
I just had mine done not long ago and mine went like this (room was already stripped back to brick)
got floor plan
Lifted all the floor including subfloor, levelled the joists
Got 1st fix electric and plumbing , a lot of services run under the floor cavity
Re laid the subfloor
room boarded and skimmed
vinyl plank flooring installed
I then painted the ceiling to save hassle later on
Kitchen installed and cables / pipes positioned ready for 2nd fix
Worktops installed
2nd fix electrics and plumbing, appliances connected - kitchen now usable
next step which I need to do is fit the Skirting boards and finish painting but it’s not far off being finished
Things to bear in mind
Spend time planning your lighting , have a good idea of where all the lights should go, the kitchen designer should help but just remember it’s a pain to change some things once you’ve plastered and skimmed
If your having a kitchen diner make sure you position your sockets and think of where you may need some in the future if you decide to move things about
if you want an integrated fridge freezer I’d recommend 2 separate tall appliances as a single does not have much space
if you don’t use a microwave much but still need one you can have a cheapish stand-alone put above an oven in a tower unit
cupboards with shelves are generally cheaper than drawers so cutting down on the amount of drawers should be cheaper, don’t splash out on proper drawers or one of those vertical slide out things, for a full height larder unit , use the shelves and buy some basket pull outs - usually a lot cheaper and just as handy
some cupboards are essential for storing large appliances such as mixers , food processors etc
have a good idea where you want your radiators to go , it’s a pain to move them if you change your mind later