Sounds like you are doing Similar to what I've just done a few months ago.
We had non supporting partition wall (not brick) taken down between kitchen and dining room. Then full kitchen refurb and separate utility room completed. Spot lights, dining table light, under unit lights, plinth lights, plastering walls, ceiling, flooring, tiling and quartz worktops, 2 new tall radiators.
It cost just short of £13K including appliances, all integrated.
We started with builders quotes and going to Howdens and Magnet. This enabled the builder to quote on our drawings. Also went to b&q just to compare, price wasn't too bad but cldnt knock the wall down n units didn't look as gd.
The builders wanted between £5.5-£6K just for the labour 😮 said it would take a week, we are in central Scotland. I had quotes from 3 builders. It was looking like costing about £15K doing it this way.
We went to a local kitchen firm just for a comparison thinking it would be more expensive but they were actually cheaper and did everything for us. Gave us a few extras for free too like new skirting boards in the bits that were missing from wall being knocked down, new bars for the floors, window sill ended up needing replaced they got us one and didn't charge, also added a small unit during the process for no extra charge.
Oh I also sourced the worktop myself, this was soooo much cheaper. Found a place and visited them they gave me samples away (decent sized off cuts).
I also got some stuff myself from EBay. Taps and sink. Kitchen place wanted £450 per radiator that I wanted, I sourced both for £195 delivered!
We started looking in January last year and we finally got it booked in July for fitting a few months later. It just took so long to get all the quotes and the drawings done. Back and forth changing the drawings, visiting show rooms etc.
Good luck, don't rush in to anything and start ur research ASAP!