Illustrious is currently in Rosyth (or at least she was earlier this week) on a minor refit.
However her future is in doubt as there is a review to be carried out as to whether she or Ocean should be kept as the LPH - the 'loser' will be decommissioned.
So the RN will have one flat top - which is chosen would no doubt depend on the criteria of the review (CVS v LPH I suppoise - could Ocean operate in the ASW role?)