Suspect you have a combination of the following :
1. People believe that STOVL potentially equals two carriers whereas CTOL definitely means only one. Both these assertions are probably false. It remains to be seen exactly what the conversion costs are - I still maintain that £1.8Bn for one is way off the mark, given that hardware costs are known.
2. Is there an undeclared £1Bn associated with Tornado GR4 extension in service? If so, light blue would like the "conversion" money for that.
3. STOVL ostensibly means being able to continue the pretence that occasional two week deployments aboard is delivering carrier strike. This allows JF Dave to spend longer ashore, making some people happier. I suspect that if SRVL is required to be practiced regularly, that will prove to be false as well.
Colour that in with a judicious mix of "the B is no longer in trouble", coupled with "They haven't solved the C hook issue yet" and there's your story.