Just posted a reply elsewhere, but I see from your title that the bowl is in fact oval, Robbo. This confirms the ID as WF 9158 in Sea Geen, and designed by Barnaby Powell.
(ID thanks to Ray Annenberg and Patrick Hogan. Ray thought it might have been Patrick's grandfather who designed it, but Patrick confirmed that it was Powell
Ray could ID it instantly as 9158 by the uneven thickness of the rim, a result of pulling the shape into an oval