RCD sockets V non RCD

If that’s what the electrician says then... why are you having individual RCD sockets? Why can’t the rings be RCD protected at the consumer unit/distribution board then use ordinary sockets. There is no price on safety though. My edit ... Fed from RCBO’s ? You left that bit out first time. Still can’t see why you need RCD individual sockets as well, unless the equipment to be used has a high earth leakage and when totalled up exceeds the limit.

Get another opinion. You don't need x2 RCD's on the same circuit. RCBO's are RCD's to the layman. Perhaps it has something to do with an expectation that equipment is likely to trip the RCBO therefore an RCD socket upstream is additional protection? I don't know, get another opinion.

All final circuits should have RCD protection, unless there is a assesment stating it is not required. In an office with lots of IT equipment there could be problem with the RCD's triping due to the high earth leakage of IT type power supplies. An RCBO can be fitted in the distrubtion board to protect a circuit, this would be feeding a number of sockets, which may cause the RCBO to trip. If each socket has RCD (no RCBO in DB) there is less chance of it tripping. You shouldn't need both RCBO in DB and RCD socket.

As you are renting, a Conditional Report (safety report) would be required. RCD / RCBO not a requirement at every socket, just required at the source thus being the consumer board. Call several electricians for free quotes which will resolve your questions. RCD at every socket will be very costly!

If a new consumer unit has been installed then the circuits should be rcd protected anyway. Split load board with the socket circuits on each mcb with surge protection to ensure it meets current regulations. RCBO’s are the safest and best practice however split load RCD boards are the cheaper safe alternative