There are some things people don't understand or take into consideration......
That primus battery, is a 200v multi pack battery that can literally kill you.
There are a couple of safe guards in place, but the possibility remains.
Someone's uncles brother Joe bob changes brake pads at home because he has changed a spare wheel once.
If anything happens, he is now liable, not the factory.
As a mechanic, you take the liability of any system worked on.
Eg, brake caliper bolt falls out, brakes don't work, car has a fatal accident.
The mechanic can(and will) go to jail for negligence /man slaughter.
I agree with the fact you should be able to choose any QUALIFIED mechanic.
Going back to the factory should NOT be mandatory.
/Rant