You certainly wouldn't see anything like that out here in earthquake territory. Looks like it would pose a far greater resistance to fire than the wood houses we have though. Seems like a really easy way to wire a home like that would be to run conduit from box to box and plaster over that.
That's exactly what is done for a plastered brick wall, except it's not conduit
per se. You chase out a channel with one of these:

Then you put "twin and earth":

aka '6242Y' into the channel, cover it with PVC capping:

nailing the edges into the wall, and finally plaster over the top.
The OP ought to acquaint himself with the Building Regulations part 'P' before embarking on any DIY re-wiring and should be aware that most work of any significance will have to be inspected by either a 'registered competent person' or a building control officer.
A note for the non-brits reading this: There is not a statutory code for electrical wiring in the UK in the same sense there is in other places. There is the IET wiring
regulations, which are misleadingly named, they are
not government regulations, merely guidelines issued by the IET. The actual government regulations are quite short and sweet, and basically boil down to electrical installations must be safe and not present a risk of fire or electrical shock. Following the IET
guidelines is generally regarded by the various bits of government as an indication that the real regulations have been met, but it does not, and never has, definitively indicated that an installation meets the statutory standards - it is quite possible to 'do it the way the book says' and produce an unsafe installation in some circumstances. An indication of this is the boilerplate wording from the Health and Safety Executive that you'll find prefixing every issue of the IET Wiring 'Regulations' in recent years, vis:
Installations which conform to the standards laid down in [this standard] are regarded by HSE as likely to achieve conformity with the relevant parts of [the legislation].