In article ,
"Jake" writes:
Some friends of mine live in a property with an ancient shower. The power
cable runs from the ceiling along the tiled wall to the top of the shower.
Presumably this was permitted in previous installations?

It still is.

The shower is now out of order, and it is likely a new shower will be
required. Is it still permitted to leave the cable in this position, or
should it be buried in the wall?

Doesn't have to be buried in the wall.
Actually, it has a higher current rating if it isn't.
As others have said, you need to check the circuit and the supply
is up to running a new shower, which should also be RCD protected.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]