DIY Kitchens great price, great product, fantastic customer service in my experience.
They have an online planner, I recommend using it before buying, unlike me 🙄.
Edit: Units are all pre built!
I would recommend getting a fitter to fit so you don’t have to.
Also make sure you remove everything, and I mean everything before starting.
This means you can get any electrical work done first, as well as plumbing that needs to be sorted before putting units in (plastering too if you are going down that route).
If you can setup a kitchen somewhere else in the house then do that before, I recommend a portable induction hob for cooking. But really if you can get away that is even better!
I can recommend quickstep flooring too, walking barefoot at the moment, no underfloor heating and it is comfortable.