There are at least two things to think about here.
Firstly, what exactly do you mean by "RCB"? that's not a commonly used acronym! To comply with current standards, your socket circuit needs both overcurrent protection and RCD protection.
* A "MCB" provides overcurrent protection.
* A "RCD" or "RCCB" provides RCD protection
* A "RCBO" provides both.
You need to understand what the devices you are looking at actually do and how they are connected. Post photos and ask if you are unsure.
Secondly you need to think about what the sockets will be used for. BS7671 does not explicitly limit the number of sockets on a circuit, but you should not design installations you anticipate will be overloaded.