1) Under the new regulations any cables in a wall need protecting by an RCD or be Ali-tube cable I will assume since coming from a socket it is RCD protected.
2) Lighting needs fusing a lot lower than sockets so I would use a switched fused connection unit would act as both switch and fuse.
If you go to projects there are general instructions on fitting lights.
To instruct anyone one does not know remote is near impossible. I can help by telling you have to overcome a odd fault you may find but a step by step instruction set is not really an option. http://www.ericpalmer.fsnet.co.uk/Lighting.html and http://www.ericmark.talktalk.net/lights.htm were both made to help people but we don't know what your existing house is like and first step would be to test the supply to see if it is suitable to use and the meters cost around £60 to hire and need skill to use.
We can hardly tell you to cut corners that we would not allow a first year apprentice to cut yet we know you are unlikely to have the skill required to do it correctly.
If you have a question about one or two aspects of what you intend to do then we will answer but the main bulk you must be able to work out for yourself.
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