install a double socket and lights in the garden

hi,

I am trying to install a double socket (for a pond pump) and some lights in the garden. I am thinking to get a RCD spur from one of the sockets in house and get it outside through an armored cable for my double sockets. Also trying to create another spur for some lighting.
I've got some good knowledge about electricity (have wired my entire house), however this mini project is new to me so i would appreciate some expert advise if I am on the right track.
1. First can I create an RCD spur from an existing indoor socket?
2. what type of armored cable i would need for the outside double socket
3. can i create another 3 amp spur from the outside sockets for lightings?
I would appreciate some comments.

Many thanks,
B

 

Coloumb just trying to bring some electricity into the garden and that is what i planned to do? Just need some expert advise if I am on the right track ....