I brought up the situation of the RCD and 50mm depth as per suggested. He didn't appear to know about the requirement
In writing ask the "company specialising in all trades renovations" to confirm that the electricians they use are all qualified to work, and certify their work, to the 17th Edition, and that they are Approved Certifiers of Construction.
If they are extending, or rewiring sections of, circuits they should not leave them with faults.and when I spoke to his boss he didn't know of the rule, but thought adding an RCD capable box would probably result in constant tripping due to minor faults in the rest of the flats old wiring.
IHNI about what the Scottish Building Regs say about this work, but in terms of the Wiring Regulations there is no compulsion to work to them and hence no compulsion to issue electrical certificates.Anyway, the final question is this: do they have to provide a certificate for the work and if so what do I do if they say I don't need one or they aren't going to give me one? Most of the information on the web relates to England and Wales so I'm unclear on the certificate situation in Scotland.
BUT, when you write to them, ask them what they do to ensure that the work they do is safe, because if they say "it is done to BS 7671" then they are saying that they issue the relevant electrical certificates.