I don't know much about UK procurement procedures, but when BAE say "working on the Main Gate 4 approval process", before we even consider technical or manufacturing issues, what scope is there for this to sit in ministerial/Treasury "in trays" for months awaiting someone with the gonads to actually make a decision, or a good time to announce one?
Given that the schedule is already tight, and there are inevitable unexpected delays/issues in all such programmes, I would say that the chances of "deploying fixed wing carrier ops again by 2020" are about zero!!! Which isn't to say there won't be pretty pictures of a few aircraft on a boat and some politician making an inaccurate statement for the media....