Fair enough. The thinking behind your decision seems very reasonable. You'll need no bigger than a 3A fuse (a 1A one would be adequate) in the switched FCU.Thanks everyone, I've decided to tap into the sockets circuit and use a switched FCU inside the cupboard under the stairs. The main reasons for deciding this over the lighting circuit is because it leaves more options open for the future - I have concrete floors and a new ceiling will of course be going back on soon. For example, it creates a more accessible point if I ever needed to feed an additional socket, stair lift or whatever else the future brings.
Kind Regards, John