The current PM has talked down the value of what he calls pointy jets and while a better emphasis on non-FJ was undoubtedly important, as with everything else it's a case of striking the right balance. Recent events seem to be pointing up that current plans do not have the balance quite right.
That is something SDSR 2015 will need to look at. For one thing, the idea that in 2019 the nascent F35 force will be able seamlessly to step into the shoes of the highly developed Tornado capability sounds more than a tad optimistic. Rescinding the decision to bring Tornado OSD forward from 2022 would be a helpful first step that would buy some breathing space, without trying to string Tornado out too far.
After that, making provision at least for a second batch of say 20 F35 to allow generation of a third front line squadron in the early mid 2020s would be proportionate and achievable. And necessary. Doing nothing more between the initial 48 and Typhoon OSD doesn't strike me as a good idea.