On the rewiring issue, the adoption of BS1363 and the ring circuit in the U.K. probably did much to encourage the removal of very old wiring. That's not to say that there weren't still some ancient installations in use in later years, but many houses were completely rewired in the 1950s/60s to the new standard and all the original 1920s/30s stuff pulled out.
Although rubber-sheathed cable was used on the earlier rewires, most rewires from the late 1950s onward used PVC.
About the only time today I see really old 1930s wiring in homes is on a lighting circuit, but even that's becoming fairly unusual now. Some of those 1950s/60s rewires were economy jobs which installed new rings for sockets but left the original lighting circuits intact.
[This message has been edited by pauluk (edited 06-05-2006).]
