Also, our handful of Type 45s are the air defence for the carrier group, and were not bought to defend our home territory - a job which can be done more sustainably from a fixed-base footing. Without the Type 45s, the carrier group would be reliant on its F-35s for air defence - the proverbial self-licking lollipop.
The T45s are "part of" as opposed to "the" air defence for a maritime force, not limited to the carrier group. Something many people seem to forget. Any maritime force, faced with a credible air threat usually needs organic f/w to protect it, for precisely the same reasons you describe vs Mr Bear. That does not make the carrier a self-licking lollipop, it just adds to the rationale for having carrier-based air.
Personally, I'd suggest that QRA is strategic, as the number 1 item in any defence "strategy" is to be able to defend the homeland from attack. Whether the UK has any other role for land based FJ is a much bigger debate.