I’ve just been involved with a Wickes kitchen install. The units were fine, though expensive (compared to Magnet).
The design was utterly useless. Their chap came round and measured up for the couple, gave them a design, which they bought.
He didnt account for pipework/water meter behind a draw unit. They have a serving hatch into the living room, he’d put a kitchen wall unit over the top half of it. The sit on top unit covered up existing pipes going upstairs, so would not fit on the avalable space without moving the pipes.
It took 2 days longer to fit it as 4 units had to go back as they’d never fit. Doors for the new units woudl take 2 weeks to be delivered.
Get your fitter involved from the start, or, if diy, go over the plans meticulously, and dont trust the salesman to plan it.