The real Ark has just come back in to service after refit earlier this year, but, that cut out sponson on the stern you are talking about has been there since the early 90s or so, before that it was on the flight deck right aft centre, it used to have a Phallanx on there. If you look at the latest pictures you will also find that Illustrious and Ark, now sport a third mast with the new radar set up that the type 45s are getting. There have been lots of other changes, including a fully plated flight deck right up to the bow, as the powers that be decided that Sea Dart was defunct, question begging, why keep 15 or so type 42s in service untill lately with Sea Dart, where, where their replacements sooner, 6 type 45s??? To replace 15 plus ships????
Something wrong there me thinks??
I hope this helps.
Paul...