http://www.talkmorgan.com/ubbthreads.php?ubb=showflat&Main=3005&Number=30224#Post30224

I use Mobil 1 5-30 but see the thread above.

You could also ask your local Jag dealer since the engine appears in the X Type and S type in different guises.
The Jag oil filter is XR8E6714AB I'm told, and I might give one a try next service.

Make sure they haven't changed the filter spec on the latest Roadster.

DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4