thanks for your suggestion. The trouble seems to be that we must adhere
to the limitations of the existing framework (where dynamic includes
were not needed yet) and swapping the stylesheets as you suggested would
not be on.

Cheers,
Ralph

That is instead of having your runtime choice pass a parameter to the
main stylesheet choose your top level stylesheet at run time, and have
all those top level stylesheets include the common code.

If you really do need to generate a stylesheet then what you described
is what Mike meant.