Ireland Exterior socket plus switch controlled light on existing spur

[Rayserb]

I want to replace an existing sensor activated exterior light with a RCD socket and a switch controlled light. Is this OK to do. So interrupt existing wire with RCD. Connect top outlet of RCD to external light switch. Connect bulkhead light to light switch?

 

[telectrix]

fit a \rcd socket if the circuit is not already on RCD. then you need a FCU fused at 5A for the lights.

 

[DPG]

Is the light fed from a lighting circuit or a socket circuit?