Isn't Rivet Joint subject to a co-manning agreement, so that to some degree it's a single force?
Regarding Wedgetails I have a lot of sympathy with Northrop's written evidence to Parliament in May 2022 which may suggest even 5 was too few. Granted go it alone ops by the UK are very, very unlikely.
If one factors in routine maintenance, failure rectification, and upgrade, a three aircraft fleet can only
guarantee two available aircraft. It is therefore immediately apparent that a three aircraft fleet cannot meet
the seemingly simple task of persistent orbit at relatively short range for a single task/ theatre. This is
obviously exacerbated further by concurrent operations and training. Previous experience in Bosnia
showed that to deploy the three aircraft needed to constitute an enduring capability took four deployed
crews and used the entirety of a seven aircraft fleet in rotation. Waivers were required to allow greater than
normal duty times for the crews.