I am fitting 2 /3 double sockets into a new conservatory, I am taking the spur from a combined 30ma rcd/13amp fcu connected to an existing 2.5 ring circuit. I may connect the additional sockets using 1.5 T&E. My question is, can I add another fcu rated at 6A to the spur and supply a single light fitting with 1.0mm t/e fitted into plastic conduit to the roof of the conservatory? this would save having to drill through the cavity wall to conect to an existing lighting circuit.