In article ,
"Brian Sharrock" writes:
I'm not a Building Control Officer ....
But I am under the impression that all 'new' buildings - post 1960-ish(?) -
had to have the soil pipe routed within the house. Certainly the new-build
house I moved into in 1965 had the stack 'internal'. Am I wrong?

I believe you were right (as a result of lots of cast iron soil
pipes freezing and cracking in the extra cold winter of 1962/3).
However, I don't believe it is the case any more, possibly as
a result of the switch to plastic pipes (and global warming;-).

--
Andrew Gabriel