That's a pretty good deal n switzerland - as long as ppl don't make dangerous equipment, or make equipment dangerous.
I found that in Queensland, it's illegal to replace even low-voltage components in electrical equipment (unless someone without electrical expertise could do it safely, e.g. replacing a fuse)(http://www.legislation.qld.gov.au/LEGISLTN/CURRENT/E/ElectricalSA02.pdf). I guess you could argue that someone without expertise could solder safely (though I think you'd lose).
Can you quote which section of the regulation you posted states that? I did find this on page 40 - section 37
"Duty of repairer of electrical equipment or electrical installation
(1) This section applies to a person (the repairer) who repairs electrical equipment or an electrical installation.
(2) The repairer must ensure that—
(a) the way the electrical equipment or installation is repaired is electrically safe; and
(b) the processes followed for repairing the electrical equipment or installation ensure that, when repaired, it will be electrically safe; and
(c) the electrical equipment or installation, when repaired, is electrically safe.
(3) Without limiting subsection (1), the duty includes ensuring that the electrical equipment or installation, when repaired, is
tested and examined to ensure it is electrically safe."
So, you originally asked if DIY repair legal. I think so, as long as you ensure the repair is safe. Therefore get it tested and tagged to ensure safety for the rest of your family.
Ozwolf