Is it possible that with the UK committing to the Hornet, that they would then join in as partners on the Super Hornet program in a similar way to the Harrier II joint development?
With Eurofighter now aborted for UK manufacturers, and the Tornado program winding down, there is going to have to be some large contract to keep domestic fighter manufacture going in the UK. Harrier II will sustain them a little while in the 90s, but local production of Super Hornets in the 2000s would be ideally placed to take up the slack. Long term planning would likely have this work being superseded by JSF construction in the late 2010s.
Going Hornet would also signal a much tighter integration of the UK aviation industry with the American one, and given that Harrier, Goshawk, Hornet and Super Hornet will all be Boeing products by the end of the 90s, its possible that we might see a Boeing-BAe merger. With the BAe operations becoming a Boeing-UK subsidiary perhaps?
If Boeing and BAe co-operate on the JSF that might also have strong implications for that program. Boeing would be able to use the REPLICA research data to strengthen their offering, and if the VTOL version is canned it might mean that the Boeing prototype wins the competition. (The X-32's major failing was in VTOL operation after all.) This may also result in increased opportunity for other British defense manufacturers. Rolls Royce for example may succeed in getting their engine selected for the JSF, something possibly supported by a closer relationship with Boeing though the UK subsidiary.
It also has wider aviation implications, in the late 2000s and 2010s Boeing sought to get a part of the short range regional airliner market, and after trying their own efforts, eventually bought into a joint venture with Embraer. However if they had already merged with BAe in the 2000s, there would be a ready made regional airliner division in the team that made the BAe 146/ Avro RJ. In fact with Boeing's backing and support it is possible that the follow on RJX is never cancelled. It is possible that this results in the continued production of passenger aircraft in Britain, with a Bombadier CRJ and Embraer E-Jet competitor aircraft being brought to market in the 2010s.