In message , robert
writes


Very many thanks for the suggestions. It looks as though the consensus
is to use caulk although it is likely to be more difficult to achieve a
finish that completely blends in with the existing surface.

In my first post I indicated that I was thinking of using an adhesive
with gap filling properties in the deeper part of the crack - my thought
was that this could help stabilise things. I wonder if anyone has any
views on this?

--
Robert