That is really something to be reported to the relevant authorities because it indicates that this "qualified electrician" did not know what he was doing and di

That is really something to be reported to the relevant authorities because it indicates that this "qualified electrician" did not know what he was doing and did not perform tests... I do DIY electric work (as much as permitted) here in the UK and I always use a socket tester to check correct wiring and Earth connection. That's a no brainer. Side comment: that's why I am always wary of properties refurbished with the aim of reselling them, or properties where the owner "has just <built extension | converted loft | etc>".