I'd put another length of clay pipe into the one in the ground and
another piece in that to make up the distance, if you can find stuff of
the right diameter.

Another way around is to locate a piece of pipe that will do it, from a
scrap yard or a metal fabricator's. I am assuming there is no plastic
bit that will join the two.

After that it is a matter of aesthetics. Can you hide the bodge with a
flower tub or some-such?

Plan C: Run a new length all the way up, outside the house and bring
all the interior plumbing out to that. That way you can use modern push
fit stuff to replace the lot. A small payback is that you can get rid
of the old boxing in later and reclaim some of the bathroom/WC etc.