Just a heads-up. There are compatibility issues between a Doepke Switch, a Gigawatt switch and the rest of the components in your consumer unit.
The best solution is a dedicated Consumer unit for the Doepke and Gigawatt, using Henley blocks to T-off 25mm2 tails directly after your meter.
What are the problems?
Firstly, the cable inlets dont align. Doepke inlet is at the front of the switch and Gigawatt at the rear, so you can‘t use a bus bar for the phase feed.
Then, the inputs are at the top of the Doepke and at the bottom of the Gigawatt, so you need a decent piece of 16mm2 cable to connect the 2 (See diagram below)
Finally, the Gigawatt switch isn’t the same depth as regular circuit breakers, so doesn’t completely fill the switch access cutout in the front cover of the consumer unit.
FYI, here’s pictures of the finished supply, the meter tails and a diagram that I handed to my electrician before he got started
Having said all that, the combination of Doepke and Gigawatt significantly outperforms my previously installed dedicated lines based on a regular RCCB and cut-out switch and German-made Klangmodul (Sound module) fuses. The extra work was well worth it.