Electrical work under SI2006 is either a) Notifiable or b) Non- Notifiable to LABC depending on work location etc. SI2006 can be downloaded from ODPM, might be SI2010 now. The law is NOT set by SI2004, some tradesmen will quote SI2004 by routine, get rid of them.
Example.
- A kitchen is considered a Special Location.
- Adding a socket in a kitchen is Notifiable Works.
- Repairing a socket or replacing a cable in a kitchen is Non- Notifiable Works.
As to separation from services... Gas BS6891-2005 8.16.2 Separation of installation pipework from other services. Where installation pipes are not separated by electrical insulating material, they shall be spaced as follows: a) at least
150mm away from electricity meters and associated excess current controls, electrical switches or sockets, distribution boards or consumer units; b) at least 25mm away from electricity supply and distribution cables.Compliance with BS7671 requires that other things may need rectifying first, for example Main Equipotential Bonding etc. Part P "P1" applies re nothing shall be required beyond that to maintain safety of people, property etc etc - BS7671 being the typical comparison standard.