Les Ward
Dear Sandy, it may be best if you get a couple of the electricians who have quoted to explain their reasons for rewiring or not rewiring. Another consideration may be how much refurbishment work you are planning to do in the property. If it is extensive it may be worth rewiring all, or the parts of the building where you are having work done at the same time. If the building was built or rewired from the late 1960's onwards it is likely to have PVC insulated wiring and unless this has been exposed to unfavourable environmental conditions, overloading or poor installation methods it is likely to be in a satisfactory condition. The condition of the wiring can be determined by inspection and electrical testing. An old electrical installation is unlikely to have the number of socket outlets that are required today and the existing sockets may be very close to the floor. If extensive additions are required to a circuit it may be best to rewire it completely. Finally but importantly, the earthing arrangements or lack of them in an old wiring system (particularly for installations pre 1966) can be a compelling reason for complete rewiring.