The message ews.net
from "Doctor Drivel" contains these words:

It may work out cheaper if ripping the place to pieces is in order to get a
to a drain pipe.

Access would depend on where the boiler went. It's in the kitchen at the
moment, but if it's moved to the airing cupboard above then it's not far
to the bathroom drainstack.

--
Skipweasel
Pay no attention to the man behind the curtain.