Two items in the brief could not physically work, and that had to be found before fabrication.
A 25 mm overlay is impossible. Aluminium-frame hinges give 17 mm at most (A = 4.5 + 12.5 − D per the Hettich catalogue). The doors overlap 14 mm and a metal angle covers the rest.
The carcass will not enter the niche assembled. Its 3037 mm diagonal exceeds the 3010 mm niche, so it is assembled on site: the top slides in from the front on the mitres, three hidden brackets per corner.
Heavy doors. A 2980 mm mirror leaf weighs 20.9 kg: six Sensys 8638i hinges per leaf and a mid-rail in the frame against bowing.
Shelf lighting without wires. Loox5 24 V busbars in the side panels and spring contacts in the shelves: a shelf can move to any height and still lights up.