What are the legal considerations of installing a new light in my own house in the UK?
If, for any reason, damage to the property or (worse) to a person should be caused by the electrical work you performed you could be held liable (at least here in the States). Having to go before a magistrate to defend your actions or paying for others injuries is stressful and a serious issue. If you are naturally adept in home repair and astute with the electrical problem then chances are your work will be sound and safe. It would be wise to not only familiarize yourself with the work to be performed (through books and videos), but to have it inspected by someone more knowledgeable.