Out of interest, is this a flat that you are waiting to live in or is it a project to rent out, if the latter then you have time in your side and from your previous posts it would seem that you had a specific placement plan, which suggests that you like a job well done. So if it was me, I would contact the Niceic and insist on an inspector being present when you have arranged for the electrician to visit, have the inspector in one room whilst you conduct a meeting with the electrician, so that the conversation can be overheard. Then introduce the electrician to the inspector and insist that a written agreement to rectify the installation to both your requirements and the regulations is drawn up with all three signatures on. This way you are getting a commitment from the Niceic to ensure this is put right at no extra expense to yourself. Agree payment upon satisfactory completion with further first and second fix inspections by the inspector. If this fails then a letter to the head of the DCLG to report the unsatisfactory workmanship of part p.