The regulations BS7671 cover Domestic, Commercial and Industrial so a regulation thats are usually applicable in a domestic are the very same that are applicable in say Industrial, there are very few regulations that are specified to be only applicable to one of these areas so the general consensus is most regulations are across the board, the use of the Reg's book should be a regular event until you have a indepth knowledge of it and any ammendments that are introduced.
We are not attacking your character or competence here but do feel the nature of this question is a little basic to be asked by a practicing Electrician.
To help out you have been cited the Regulations you need to re-cap on and are relevent to your question.
If you are extending, altering or installing new then any of these points will have to meet current regulations regardless of when the previous was installed, in the case of your question then, you would be required to ensure your new sockets have rcd protection, now because the cables you install are within a dado system then the new cables are not subject to requiring rcd cover so a cheap solution is to fit rcd socket outlets. The alternatives are you fit front end rcd cover and then you will be subject to calculating design leakage from the IT equipment and probably dividing the ring into smaller circuits to spread the leakage between rcd's ...
We are happy to help but we need a sense that your trying to help yourself rather than just asking a direct question without showing what you think about the situation yourself.
In all honesty you come across as though you haven't got a copy of the regulations or have an outdated copy an are unable to reference the regulations yourself, as I said, its not hard to locate these regulations and they have been given to use to look up.
There are exemptions to fitting RCD cover on sockets but you should be avoiding trying to find reasons to loose personal protection of a circuit that usually requires an rcd and as the yellow book is redifining the how some of these exemptions are applied it also is trying to ensure dropping rcd protection has a very good reason.... I would suggest one good reason is a radial socket at home for a dialysis machine where a nuisance trip is actually more life threatening than keeping the afforded protection and in such a case I would also fit a T pin socket to ensure standard plugs don't get used in it.
Again the regulation of the requirements for standard sockets to be rcd protected is one that should be well and truely embedded in your knowledge, I can forgive not fully understanding the excemptions but thats not what you enquired about.
I would ask in your future threads that you attempt to show your at least referencing regulations - not understanding regs is common as many are ambiguous and thats definately what the site is about, giving info to members who consider the regualtions to be nothing more than a step to pass exams and can be forgotten after by using rule of thumb or tricks of the trade then this is not what we are about and will be clear if we feel you should be helping yourself more.
Note - you need the new regs anyway within 2 months or how you going to sign your work off as the Zs permitted values have now changed along with a good chunk of regulations some of which are slightly relevent to the question you posed.
You cannot be a competent practicing Electrician without a copy of the regulations in some format or other, I find it very hard to believe tbh.
I've been more than kind enough here to give you the direct answer but also advice I hope you take in