You have a number of issues here that do not reach the required standards of BS7671:2008 (AMD1) and other building regulations
Most have been mention:
*The sheath of cable not entering an enclosure.
*Joints not being enclosed.
*Exposed live conductors.
*The positioning of the fitting near a combustible material.
*The insulation be removed, therefore compromising the thermal resistance of this barrier. Although the lamps and any connected transformers must be ventilated and the evidence of the picture does really show how extensive the actual thermal layer is!
*12V lamps on 240V supply.
*No issuing of either an electrical insulation cert or minor works cert.
If you have the details (on invoice, quote, receipt etc)
You could google to see if the are registered as competent person in the eyes of the law:
http://www.competentperson.co.uk/
Enter the details given and they should appear on the list or the scheme provider maybe on their paperwork.
Once you have done this and confirmed either way you have options.
*Call the electrician inform them that you are not satisfied with the quality or safety of the work and it has a number of issues that are not compliant to BS761 as stated on their paperwork that he has made it so. And you would like this correcting or your money back, so you can find an alternative electrician to carry out the issues that need addressing.
*Inform their scheme provider as they will have a complaints procedure which will be logged against them.
*Contact trading standards and make a report against them, you must first though make contact with the person who performed this work to try to come to a resolution as they will ask if you have before they then contact them.
*You could also talk to your LABC and inform them that you have had electrical work installed by an alleged electrician and evidence would suggest that it does not comply to Part P of the building regulations, as it is unsafe.
And you would like to know what procedures are in place to address this legally? Please not we are not talking about notification of the work if asked, simple that it is unsafe and none compliant to BS7671.