I have taken the sump off a 1159cc engine and found that rather than the piece of cork that you get in most sump gasket sets there is a neoprene rubber half circle with tabs - see photo - seems a much better implementation.
I also noted that the sump gasket was made of a cork and aluminium sandwich - part of a more expensive sump gasket set I assume.
Does anyone have any background to this?
I will see if my gasket man has a source of the neoprene rubber part.